Magnetic memory and method for manufacturing same

Abstract

In order to provide a magnetic thin wire memory in which a shift error of a magnetic wall can be prevented or reduced, and for which the manufacturing process is simple, a magnetic memory and a method for the magnetic memory are provided. The magnetic memory comprises an adjacent material layer made of a non-magnetic body adjacent to a magnetic thin wire layer including first and second regions. Third and fourth regions of the adjacent material layer are respectively adjacent to the first and second regions of the magnetic thin wire layer in the thickness direction. The third and fourth regions of the adjacent material layer are composed of different materials. The intrinsic coercive force or the product of the intrinsic coercive force and the intrinsic magnetic anisotropic magnetic field of a magnetic body in the second region of the magnetic thin wire layer is greater than the intrinsic coercive force or the product of the intrinsic coercive force and the intrinsic magnetic anisotropy magnetic field of the magnetic body in the first region of the magnetic thin wire layer. Alternatively, the electrical conductivity of the second region of the adjacent material layer is higher than the electrical conductivity of the first region thereof, and the threshold current density of the second region of the magnetic thin wire layer is greater than the threshold current density of the first region thereof.

Description

Magnetic memory and manufacturing method thereof

[0001] The present invention relates to a magnetic memory, in particular a magnetic nanowire memory and a manufacturing method thereof, and in particular to provide a magnetic nanowire memory capable of reducing shift errors.

[0002] To realize Society 5.0, which aims to create new value through comprehensive sensing and big data analysis, it is essential to develop high-capacity, high-speed, and non-volatile storage for mobile devices and data centers. Three-dimensional (3D-) NAND flash, which vertically stacks NAND flash memory that stores data by storing electric charge in the gate insulating film of field-effect transistors, has been put to practical use as a storage device that meets these requirements.

[0003] Currently, the amount of data generated annually is several tens of ZB (zettabyte: 10E21). If the recent growth rate continues, at 26% per year, this amount is expected to exceed 500 ZB per year by 2030. To store this vast amount of data, measures such as multi-layering 3D-NAND flash have been proposed. However, the recording density of 3D-NAND flash is reaching its limit due to the presence of transistor gate electrodes. Therefore, a fundamental change in the recording principle that does not use transistor structures is necessary to accommodate the continuing information explosion.

[0004] Domain wall-driven magnetic nanowire memory (hereafter simply referred to as magnetic nanowire memory) is a nonvolatile memory that utilizes the magnetic domain structure of magnetic materials and is attracting attention as a new alternative to 3D-NAND flash. A magnetic nanowire consists of either a single magnetic layer that forms magnetic domains (spin transfer torque type) or a nonmagnetic layer with a strong spin Hall effect and a magnetic layer that forms magnetic domains (spin orbit torque type). In spin orbit torque type magnetic nanowire memory, a nonmagnetic layer with a strong spin Hall effect (heavy metal or topological insulator) bonded to the magnetic layer functions as a pure spin current source. When the pure spin current generated by the nonmagnetic layer acts on the domain wall, a spin orbit torque is generated, causing the domain wall to move. The direction of domain wall movement can be controlled by the direction of the current.

[0005] Japanese Patent Application Publication No. 2021-149993 Japanese Patent Application Publication No. 2022-45204 Japanese Patent Application Publication No. 2013-297174 Japanese Patent Application Publication No. 2010-99096

[0006] SSP Parkin, Science (2008)

[0007] Magnetic nanowire memory has performance that surpasses that of 3D-NAND flash, thanks to the write / read technology developed for magnetoresistive memory and the extremely fast domain wall motion speed of 100 to 1000 m / s. Furthermore, if 3D-magnetic nanowire memory can be realized, the recording density of 3D-NAND flash can be exceeded by more than an order of magnitude. Therefore, 3D-magnetic nanowire memory is very promising as a new memory that will support the next-generation information society. However, memory has a unique problem called shift error caused by domain wall motion.

[0008] Magnetic nanowire memory drives magnetic domains by applying a pulse current to the magnetic nanowire. At this time, the amount of magnetic domain shift is determined by the pulse width of the pulse current and the speed at which the magnetic wall moves. Because the pulse width is determined by the characteristics of the transistor-based drive system, it is possible to keep variations small. On the other hand, because the speed at which the magnetic wall moves is determined by various factors, such as the magnetic properties and crystallinity of the magnetic nanowire, there is generally variation in characteristics between multiple nanowires. This variation in the speed at which the magnetic wall moves causes variations in the amount of magnetic domain shift per pulse between nanowires, a phenomenon known as a shift error, and it can cause write and read errors.

[0009] To suppress the shift error, the threshold current density j is the minimum current density required for the domain wall motion. ｔｈ In both 2D- and 3D-magnetic nanowires, the threshold current density j ｔｈTo achieve spatial control of the memory structure, shape changes in magnetic nanowires have been used (Patent Documents 1 and 2). Because 2D-magnetic nanowire memory involves forming magnetic nanowires on the surface of a substrate, specific structural changes can be easily introduced through an etching process. On the other hand, because 3D-magnetic nanowire memory involves forming magnetic nanowires on the sidewalls of holes with a large aspect ratio formed in a substrate, the shape of the sidewalls must be specifically controlled in advance. However, it is extremely difficult to consistently create specific shapes in high-aspect-ratio holes, which can lead to problems such as increased process costs and reduced reliability due to variability.

[0010] It has been proposed to increase the threshold current density by providing a domain wall pinning layer adjacent to the magnetic nanowire, which is composed of a nonmagnetic region and a magnetic region (ferromagnetic region), in order to control the threshold current density of the magnetic nanowire (Patent Document 3). In this proposal, the intrinsic magnetic anisotropy of the magnetic nanowire is the same in all regions of the magnetic nanowire, and a magnetic field bias is applied to the magnetic nanowire by a leakage field from an external magnetic material (magnetic region) or ferromagnetic exchange coupling. This differs from the present disclosure, which changes the intrinsic magnetic anisotropy of the magnetic nanowire depending on the region. The proposal in Patent Document 3 is merely an idea and cannot be used as a magnetic memory for the following reasons. That is, the magnetization direction written in the magnetic nanowire can be either the same or opposite to the magnetic field bias direction based on the adjacent magnetic region. Therefore, the magnetic field bias has a domain wall pinning effect on the magnetization written in the same direction as the magnetic field bias, but the magnetic field bias acts to facilitate domain wall movement for the magnetization written in the opposite direction to the magnetic field bias, thereby increasing shift errors. Therefore, it cannot be used for domain wall pinning in a magnetic memory.

[0011] Another proposal is to provide an antiferromagnetic region made of an antiferromagnetic material adjacent to a ferromagnetic material layer serving as a magnetic nanowire, and to fix the magnetization direction of the ferromagnetic material layer by the exchange coupling between the ferromagnetic material layer and the antiferromagnetic region (Patent Document 4). This proposal also differs from the present disclosure, in that the intrinsic magnetic anisotropy of the magnetic nanowire is the same throughout the entire magnetic nanowire, and a magnetic field bias is applied to the magnetic nanowire by an external antiferromagnetic region. This differs from the present disclosure, in that the intrinsic magnetic anisotropy of the magnetic nanowire itself is changed depending on the region. This proposal utilizes the fact that, although the antiferromagnetic region as a whole is not magnetic, focusing on a single atomic layer at the interface of the antiferromagnetic region adjacent to the ferromagnetic material layer, it is possible to align the spins in one direction at the interface, thereby exerting a magnetic effect on the ferromagnetic material layer. Ultimately, this proposal can be said to have a similar effect to the magnetic field shift in Patent Document 3. Therefore, the proposal in Patent Document 4 also suffers from the same defects as those in Patent Document 3 and cannot be used for domain wall pinning in magnetic memories.

[0012] Furthermore, the ferromagnetic region proposed in Patent Document 3 and the antiferromagnetic region proposed in Patent Document 4 need to be initialized to determine the direction of the bias magnetic field, which requires an increase in manufacturing equipment that applies a magnetic field or performs heat treatment while applying a magnetic field, leading to an increase in manufacturing costs.

[0013] Furthermore, in the proposals of Patent Documents 3 and 4, when three-dimensional magnetic nanowires are arranged on opposing side surfaces of a vertical vertical hole, the directions of domain wall motion are reversed for the magnetic nanowires on the left and right sides of the vertical hole, whereas the directions of the bias magnetic fields due to the ferromagnetic layer in Patent Document 3 and the antiferromagnetic layer in Patent Document 4 must be the same for the magnetic nanowires on the left and right sides of the vertical hole after initialization. As a result, the bias magnetic fields due to the ferromagnetic layer proposed in Patent Document 3 and the antiferromagnetic layer proposed in Patent Document 4 reverse the domain wall pinning action relative to the domain wall motion of the left and right magnetic nanowires arranged on opposing side surfaces of the vertical vertical hole, and therefore cannot be used for domain wall pinning of the three-dimensional magnetic nanowire.

[0014] In this disclosure, we have developed a technology that can locally control the threshold current density, which is the current density required for domain wall motion, even at the order of magnitude by controlling the material adjacent to the magnetic nanowire. This makes it possible to reduce shift errors without modifying the vertical shape. Furthermore, by reducing the process difficulty, reliability is improved and process costs can be reduced.

[0015] The present disclosure includes the following aspects: (Aspect 1) A magnetic memory having a first direction and a second direction intersecting the first direction, comprising: a substrate; a magnetic wire layer including a magnetic layer or a magnetic layer and a spin Hall layer, and including a first region and a second region in the first direction as a data storage region; an adjacent material layer existing adjacent to the magnetic wire layer in the second direction and made of a non-magnetic material having no intrinsic magnetization, the adjacent material layer including a third region and a fourth region in the first direction, the third region existing in the second direction of the first region, and the fourth region existing in the second direction of the second region; and a circuit applying a pulse current to the magnetic wire layer to move a domain wall in the magnetic layer in a direction from the first region to the second region; wherein a first material constituting the third region and a second material constituting the fourth region of the adjacent material layer are different materials and satisfy the following requirements A and B: A) the first material and the second material of the adjacent material layer are materials that can induce magnetic anisotropy in the magnetic layer of the first region and the second region of the magnetic wire layer, and the intrinsic coercivity of the magnetic layer of the second region of the magnetic wire layer is greater than the intrinsic coercivity of the magnetic layer of the first region of the magnetic wire layer, or the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer of the second region of the magnetic wire layer is greater than the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer of the first region of the magnetic wire layer (Feature A); and B) the electrical conductivity of the fourth region of the adjacent material layer is higher than the electrical conductivity of the third region (Feature B), the first region of the magnetic wire layer has a first threshold current density, and the second region of the magnetic wire layer has a second threshold current density, wherein the first threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer required to move a domain wall in the magnetic layer in the first region, and the second threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer required to move a domain wall in the magnetic layer in the second region, and the second threshold current density is greater than the first threshold current density;(Aspect 2) In the case of the above-mentioned aspect A, the difference in the intrinsic coercivity or the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer between the first region and the second region of the magnetic layer is due to a difference in the crystal structure or crystal orientation of the magnetic layer between the first region and the second region, the difference in the crystal structure or crystal orientation of the magnetic layer between the first region and the second region is due to the influence of the material of the third region and the material of the fourth region of the adjacent material layer, and the difference between the first threshold current density and the second threshold current density of the magnetic layer is a difference in the threshold current density of the magnetic wire layer itself observed in a current flowing through the magnetic wire layer itself in its length direction under the condition that there is no influence of a magnetic field or electric field in the cross-sectional direction of the magnetic wire layer, In the case of form B, the difference between the first threshold current density and the second threshold current density of the magnetic wire layer is the result of causing a difference in the proportion of the pulse current flowing through the first region of the magnetic wire layer and the third region of the adjacent material layer, and a difference in the proportion of the current flowing through the second region of the magnetic wire layer and the fourth region of the adjacent material layer, based on the difference in electrical conductivity between the third region and the fourth region of the adjacent material layer, resulting in a difference in the amount of current flowing through the magnetic layer in the second region of the magnetic wire layer and the magnetic layer in the first region. (Aspect 3) The magnetic memory according to aspect 1, wherein in the case of aspect A, the coercivity or the product of the coercivity and the magnetic anisotropy field of the magnetic layer in the second region is 1.5 times or more larger than the coercivity or the product of the coercivity and the magnetic anisotropy field of the magnetic layer in the first region, and in the case of aspect B, when the magnetic wire layer includes the magnetic layer but not the spin pole layer, the amount of current flowing through the second region of the magnetic wire layer is reduced by at least 20% compared to the amount of current flowing through the first region, and when the magnetic wire layer includes the magnetic layer and the spin pole layer, the amount of current flowing through the spin Hall layer in the second region of the magnetic wire layer is reduced by at least 5% compared to the amount of current flowing through the spin Hall layer in the first region. (Aspect 4)The magnetic memory according to Aspect 1, wherein in the case of A, the adjacent material layer is formed on the substrate side of the magnetic nanowire layer, and in the case of B, the adjacent material layer is formed on at least one of the substrate side and the side opposite to the substrate of the magnetic nanowire layer. (Aspect 5) The magnetic memory according to Aspect 1, wherein the material of the fourth region of the adjacent material layer is CrOx, and the material of the third region of the adjacent material layer is selected from GdOx, NiOx, and MgO. (Aspect 6) The magnetic memory according to Aspect 1, wherein the third region of the adjacent material layer is a nonmagnetic material without intrinsic magnetization and an insulating material, and the fourth region of the adjacent material layer is a nonmagnetic material without intrinsic magnetization and a metal or a conductive semiconductor. (Aspect 7) The magnetic memory according to Aspect 1, wherein the magnetic nanowire layer includes a spin Hall layer adjacent to the magnetic layer on the side of the adjacent material layer or on the side of the magnetic layer opposite to the adjacent material layer. (Aspect 8) A substrate having a surface including a third direction and a fourth direction intersecting each other, a direction perpendicular to the surface being a fifth direction, the surface side of the substrate being upward in the fifth direction, the adjacent material layer being on the substrate, and a first groove extending in the fourth direction from the adjacent material layer side toward a bottom surface of the substrate in the fifth direction, the first groove having a first wall surface on one side in the third direction and a second wall surface and a bottom surface on the other side in the third direction, the adjacent material layer being present on at least both the first wall surface side and the second wall surface side of the first groove, the adjacent material layer including a first portion having the first wall surface and a second portion having the second wall surface, the adjacent material layer including the third region and the fourth region aligned in the fifth direction in both the first portion and the second portion, the magnetic nanowire layer exists continuously from above the first wall surface, through above the bottom surface of the first groove, to above the second wall surface, and a second groove exists between the magnetic nanowire layer on the first wall surface and the magnetic nanowire layer on the second wall surface, the second groove extending in both the fourth direction and the fifth direction;the magnetic wire layer includes a fifth region extending above the first portion of the adjacent material layer in the fifth direction, a sixth region extending above the second portion of the adjacent material layer in the fifth direction, and a seventh region on the bottom surface of the first groove, a write unit provided in the seventh region of the magnetic wire layer, a read unit provided in the seventh region of the magnetic wire layer, and a pair of wires for applying a pulse current between the fifth region and the sixth region of the magnetic wire layer. (Aspect 9) A magnetic memory assembly including a plurality of the magnetic memories according to any one of Aspects 1 to 8 and a control unit for controlling the plurality of magnetic memories, wherein the magnetic memory includes a write unit, a read unit, first and second wires for applying the pulse current, a third wire connected to the write unit, and a fourth wire connected to the read unit. (Aspect 10) A method for manufacturing a magnetic memory, the magnetic memory having a first direction and a second direction intersecting the first direction, the manufacturing method comprising: providing an adjacent material layer made of a non-magnetic material on a substrate, the adjacent material layer including a third region and a fourth region in the first direction, wherein a first material constituting the third region and a second material constituting the fourth region of the adjacent material layer are different materials from each other; forming a magnetic nanowire layer on the substrate, the magnetic nanowire layer including a magnetic layer or a magnetic layer and a spin Hall layer, the magnetic nanowire layer being adjacent to the adjacent material layer in the second direction and including a first region and a second region in the first direction as a data storage region, the first region existing in the second direction of the third region, and the second region existing in the second direction of the fourth region; wherein the adjacent material layer is one of the following A and B:A) the first material and the second material of the adjacent material layer are materials that can induce magnetic anisotropy in the first region and the second region of the magnetic wire layer, and the first material and the second material of the adjacent material layer are selected so that the intrinsic coercivity of the magnetic layer in the second region of the magnetic wire layer is larger than the intrinsic coercivity of the magnetic layer in the first region of the magnetic wire layer, or the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer in the second region of the magnetic wire layer is larger than the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer in the first region of the magnetic wire layer (Feature A); and B) the fourth region of the adjacent material layer is selected so that the electrical conductivity is higher than the electrical conductivity of the third region (Feature B), and a circuit is provided that applies a pulse current to the magnetic wire layer to move a domain wall in the magnetic layer, a first region of the magnetic wire layer formed adjacent to the adjacent material layer having a first threshold current density, and a second region of the magnetic wire layer having a second threshold current density, wherein the first threshold current density refers to a minimum current density of the pulse current to be applied to the magnetic wire layer that is necessary to move a domain wall in the magnetic layer in the first region, and the second threshold current density refers to a minimum current density of the pulse current to be applied to the magnetic wire layer that is necessary to move a domain wall in the magnetic layer in the second region, and the second threshold current density is greater than the first threshold current density. (Aspect 11) The magnetic memory comprises the magnetic nanowire layer, the adjacent material layer, and the circuit on a substrate, a surface of the substrate including an eleventh direction and a twelfth direction intersecting with each other, and a direction intersecting with the surface of the substrate is a thirteenth direction; and depositing a first band of the first material and a second band of the second material on the substrate in the thirteenth direction as the adjacent material layer.forming a first groove in the adjacent material layer on the substrate, the first groove extending in the thirteenth direction and the twelfth direction from the adjacent material layer toward the substrate, the first groove being formed to penetrate the first band and the second band, so that in a vertical cross section including the eleventh direction and the thirteenth direction, the first groove has a first wall surface on one side of the first groove in the eleventh direction, a second wall surface on the other side, and a bottom surface, and a first portion of the adjacent material layer having the first wall surface on the one side of the first groove, and a second portion of the adjacent material layer having the second wall surface on the other side of the first groove; depositing the magnetic wire layer continuously extending from above the first portion of the adjacent material layer in the thirteenth direction, via the first wall surface of the adjacent material layer, the bottom surface of the first groove, and the second wall surface of the adjacent material layer, to above the second portion of the adjacent material layer in the thirteenth direction, the deposited magnetic wire layer having a second groove extending in the thirteenth direction and a twelfth direction between the magnetic wire layer on the first wall surface and the magnetic wire layer on the second wall surface; when the substrate is viewed from the thirteenth direction, the magnetic wire layer has a third portion extending in the eleventh direction, and fourth and fifth portions present on both sides of the third portion in the twelfth direction and extending in the eleventh direction, and isolating the third portion of the magnetic wire layer by selectively removing the fourth and fifth portions of the magnetic wire layer; and the first band of the first material is the third region of the adjacent material, and the second band of the second material is the fourth region of the adjacent material. (Aspect 12) The method for manufacturing a magnetic memory according to Aspect 11 or 12, wherein the deposition of the magnetic nanowire layer includes depositing the magnetic layer and depositing a spin Hall layer adjacent to the magnetic layer on at least one of the side of the adjacent material layer or the side of the magnetic layer opposite to the adjacent material layer. (Aspect 13)A method for manufacturing a magnetic memory described in aspect 11 or 12, wherein the first groove is formed by anisotropic etching in the thirteenth direction, and the first wall surface and the second wall surface of the first groove and the surface of the deposited magnetic nanowire layer on the second groove side are straight lines in a vertical cross section including an axis in the thirteenth direction.

[0016] According to the present disclosure, the threshold current density j of a magnetic nanowire can be controlled without using a shape change. ｔｈ By controlling the threshold current density j, it is possible to simultaneously reduce the process difficulty and cost and the shift error, and to realize a highly reliable 3D magnetic nanowire memory. ｔｈ By controlling the threshold current density j ｔｈ According to the magnetic nanowire memory structure of the present disclosure, the process difficulty and cost can be kept relatively low.

[0017] FIG. 1(a) shows the basic configuration of a magnetic nanowire memory, and FIG. 1(b) schematically shows how magnetic domains (bits) move spatially within a magnetic nanowire when a pulse current is applied to the magnetic nanowire from a driving unit. FIG. 2 schematically shows an example of a preferred three-dimensional magnetic nanowire memory according to the first embodiment of the magnetic memory of the present disclosure. FIG. 3 is a diagram illustrating parameters that determine the threshold current density of a magnetic nanowire. FIG. 4(a) schematically shows the magnetization (M)-magnetic field (H) characteristic curve of a magnetic body in the absence of an external magnetic field, and FIG. 4(b) shows the magnetization (M)-magnetic field (H) characteristic curve of a magnetic body in the presence of an external magnetic field. FIG. 5(a) shows the coercive force H of a magnetic body layer measured after forming a ferromagnetic body layer on an adjacent material (underlayer). ｃ and the magnetic anisotropy field H ｅｆｆ ｋ 5(b) and (c) show the stacked structure of the measurement sample in the measurement. ｃ The measurement sample and the measurement results are shown in Fig. 7. ｅｆｆ ｋ1 shows the measurement sample and the measurement results. FIG. 8 shows several examples of the configuration of the writing member 9 of the magnetic memory. FIGS. 9(a), 9(b), 9(c), and 9(d) are diagrams explaining writing by spin injection in the magnetic memory. FIG. 10 shows the results of a simulation in which the magnetic domain written by the writing unit is moved and expanded. FIG. 11 shows a modified example of the magnetic memory shown in FIG. 2. FIGS. 12(a) and 12(b) are diagrams explaining writing by applying a magnetic field to the magnetic memory. FIG. 13 shows several examples of the configuration of the reading member 10 of the magnetic memory. FIG. 14A(a) is a schematic diagram showing the storage area of ​​the magnetic memory of FIG. 2, and FIG. 14(b) is a schematic diagram showing the storage area of ​​the magnetic memory of FIG. 14A(a). FIG. 14B(a) is a schematic diagram showing the storage area of ​​the magnetic memory of FIG. 14A, and FIG. 14B(b) shows the pulse sequence of the drive current. 14C(a) is a schematic diagram showing a storage region of the magnetic memory of FIG. 14A, and FIG. 14C(b) shows a pulse sequence of a driving current. FIG. 14D(a) is a schematic diagram showing a storage region of the magnetic memory of FIG. 14A, and FIG. 14D(b) shows a pulse sequence of a driving current. FIG. 14E(a) is a schematic diagram showing a storage region of the magnetic memory of FIG. 14A, and FIG. 14E(b) shows a pulse sequence of a driving current. FIG. 14F(a) is a schematic diagram showing a storage region of the magnetic memory of FIG. 14A, and FIG. 14F(b) shows a pulse sequence of a driving current. FIG. 15 schematically shows an example of a preferred three-dimensional magnetic nanowire memory according to the second embodiment of the magnetic memory of the present disclosure. FIG. 16 shows a modified example of the magnetic memory shown in FIG. 15. FIG. 17(a) is a partial cross-sectional view of the stacked structure of the magnetic memory 1-3 of the third embodiment, and FIG. 17(b) is a partial cross-sectional view of the stacked structure of the magnetic memory 1-4 of the fourth embodiment. FIG. 17(c) is an overall image of the stacked structure of the magnetic memory 1-4 of the fourth embodiment. FIG. 18 shows the results of a current shunting effect test for an STT-type stacked structure. FIG. 19 shows the results of a current shunting effect test for an SOT-type stacked structure. FIGS. 20A(a) and 20B(b) show steps in a method for manufacturing a three-dimensional magnetic memory. FIGS. 20B(c) and 20B(d) show steps subsequent to the method for manufacturing the three-dimensional magnetic memory shown in FIG. 18A. FIGS. 21A(a) and 21A(b) show steps in a method for manufacturing a three-dimensional magnetic memory subsequent to FIG. 21B.Figures 21B(c) and (d) show steps subsequent to Figure 21A and the series of steps in the method for manufacturing a 3D magnetic memory. Figures 21B(e) and (f) show steps subsequent to Figure 21B and the series of steps in the method for manufacturing a 3D magnetic memory. Figure 21B(g) shows steps subsequent to Figure 21C and the series of steps in the method for manufacturing a 3D magnetic memory. Figure 22 shows an example of a memory cell assembly.

[0018] <Magnetic Memory> The magnetic memory of the present disclosure is a domain wall motion type magnetic nanowire memory (also simply referred to as a magnetic nanowire memory). Several embodiments of the present disclosure will be described below with reference to the drawings, but it should be noted that the magnetic memory of the present disclosure is not limited to these embodiments. In particular, the magnetic nanowire memory of the present disclosure is particularly effective in 3D-magnetic nanowire memories. While the following description will mainly use an example of a 3D-magnetic nanowire memory, it is also effective in 2D-magnetic nanowire memories (2D-racetrack memories). Furthermore, the magnetic nanowire memory of the present disclosure is particularly effective in memories using magnetic nanowires with perpendicular anisotropy magnetization, but can also be applied to memories using magnetic nanowires with horizontal anisotropy magnetization.

[0019] (Configuration of Magnetic Nanowire Memory) Figure 1(a) shows the basic configuration of a magnetic nanowire memory. A magnetic nanowire memory consists of four parts: a magnetic nanowire, a pulsed current generator (driver), a write unit, and a read unit. Information is recorded by the magnetization direction of the magnetic nanowire. The magnetic nanowire layer forms the data storage area. A region in a magnetic nanowire with a uniform magnetization direction is called a magnetic domain, and the smallest magnetic domain that can be generated in a magnetic nanowire corresponds to one bit. As shown in Figure 1(a), if multiple bits have the same magnetization direction, one magnetic domain can contain multiple bits. When a pulsed current is applied to the magnetic nanowire, the domain walls of all magnetic domains move the same spatial distance, making it possible to move all magnetic domains (bits) the same spatial distance. Therefore, all bits in the magnetic nanowire can be written and read using just one read unit and one write unit. (Non-Patent Document 1) Although not shown in Figure 1(a), the magnetic nanowire includes a magnetic layer or a magnetic layer and a spin Hall layer, and in this disclosure, the entire layer including the magnetic layer or the magnetic layer and the spin Hall layer is referred to as a magnetic nanowire layer or a magnetic nanowire.

[0020] The term "magnetic nanowire" has conventionally referred to a magnetic layer or an entire layer including a magnetic layer and a spin Hall layer, and is sometimes used to refer to only the magnetic layer, distinguished from the spin Hall layer. However, in this disclosure, a layer including a magnetic layer or an entire layer including a magnetic layer and a spin Hall layer is defined and expressed as a "magnetic nanowire layer." A magnetic nanowire layer includes a magnetic layer or a magnetic layer and a spin Hall layer, but may include additional layers as long as the function of the magnetic nanowire is not lost. In one preferred embodiment, the magnetic nanowire layer may include only a magnetic layer or a magnetic layer and a spin Hall layer.

[0021] Magnetic nanowire memory has performance that surpasses that of 3D-NAND flash, thanks to the write / read technology developed for magnetoresistive memory and an extremely fast domain wall motion speed of 100 to 1000 m / s. Furthermore, if 3D-magnetic nanowire memory can be realized, the recording density of 3D-NAND flash can be exceeded by more than an order of magnitude. Therefore, 3D-magnetic nanowire memory is very promising as a new memory that will support the next-generation information society. Table 1 compares the memory performance of 3D-NAND, 2D-magnetic nanowire memory, and 3D magnetic nanowire memory.

[0022] However, when a pulse current (electron current or hole current) is applied to the magnetic nanowire from the driver, the magnetic domain (bit) moves spatially within the magnetic nanowire. As shown in Figure 1(b), ideally, the magnetic domain moves exactly one bit (middle right). However, in reality, the domain wall tends to move too little (top right) or too much (bottom right), resulting in variations in the amount of domain wall movement, which can cause errors in writing and reading data. This is because there are variations in the threshold current density between the magnetic nanowires, which causes variations in the amount of domain wall movement even when the same current is applied.

[0023] In the present disclosure, the "intrinsic coercivity" and "intrinsic magnetic anisotropy field" of the magnetic layer are the coercivity and magnetic anisotropy field inherent in the magnetic layer 4 itself, i.e., the coercivity and magnetic anisotropy field of the magnetic layer itself under conditions where there is no influence of an external electric field or magnetic field. The "intrinsic coercivity" and "intrinsic magnetic anisotropy field" of the magnetic layer can be measured by measuring a sample using a known method for measuring coercivity and magnetic anisotropy field when the magnetic layer is in a state where there is no external electric field or magnetic field. Furthermore, when the magnetic layer of the sample is in a state where there is an influence of an external magnetic field or electric field, the intrinsic coercivity and intrinsic magnetic anisotropy field can be calculated by measuring the sample using a known method for measuring coercivity and magnetic anisotropy field and then subtracting the influence of the external magnetic field or electric field. In many cases, the influence of the external magnetic field or electric field can be determined from the measurement results of the coercivity and magnetic anisotropy field themselves, but if necessary, the influence of the external magnetic field or electric field can be determined separately by measurement or simulation. The details of the method for measuring the coercive force and the magnetic anisotropy field will be described later in connection with the examples. For simplicity, in the present disclosure, the "intrinsic coercive force" and the "intrinsic magnetic anisotropy field" will be (sometimes) simply referred to as the "coercive force" and the "magnetic anisotropy field".

[0024] In the present disclosure, the intrinsic coercivity or intrinsic magnetic anisotropy field of the magnetic layer 4 is different between the first region and the second region, whereas in Patent Documents 3 and 4, the apparent coercivity or magnetic anisotropy field of the magnetic layer and ferromagnetic material layer as a magnetic nanowire may be different from the coercivity or magnetic anisotropy field of the region in contact with the non-magnetic phase and insulating layer due to the influence of a bias magnetic field based on an adjacent magnetic phase or antiferromagnetic material, but the intrinsic coercivity or intrinsic magnetic anisotropy field of the magnetic layer and ferromagnetic material layer is the same in all regions.

[0025] Referring to Figure 4(a), the magnetization (M)-magnetic field (H) characteristics of a magnetic body are shown schematically. The characteristic curve of a magnetic body (hereinafter simply referred to as a magnetic body) that has undergone initial magnetization forms a loop. When the magnitude of an external magnetic field (also simply referred to as a magnetic field) H applied in the opposite direction to the magnetization direction of the magnetic body is increased, the magnetization M is initially opposite to the direction of the magnetic field H (fourth quadrant of the graph). The magnitude of the magnetic field H when the magnetization M becomes zero and then increases is the coercive force Hc (fourth and first quadrants of the graph). When the magnetization direction of the magnetic body is opposite to that described above, applying a magnetic field H in the opposite direction to the above results in a symmetrical change in the magnetic field (H)-magnetization (M) (second and third quadrants of the graph). In the graph of Figure 4(a), the two coercive forces Hc that appear due to the two opposite magnetic fields H are in opposite magnetic field directions but have the same absolute value.

[0026] In contrast, when a magnetic layer is provided adjacent to a ferromagnetic material layer (magnetic material to be measured) as in Patent Document 3, when the magnetization-magnetic field of the ferromagnetic material layer is measured, in addition to the external magnetic field H for measurement, a bias magnetic field Ha based on the adjacent magnetic layer is applied to the ferromagnetic material layer.Therefore, when the positive external magnetic field H is in the opposite direction to the direction of the magnetic field Ha, the magnetization-magnetic field characteristic curve of the ferromagnetic material layer is the curve of Figure 4(a) shifted by the magnitude of the magnetic field Ha based on the magnetic layer in the positive direction of the magnetic field H on the horizontal axis, as shown in Figure 4(b). Therefore, the coercive force Hc(1) of the ferromagnetic material layer in the positive magnetic field direction appears to increase to Hc(1) = (Hc + Ha), which may result in a domain wall pinning effect. However, as described in the prior art section, the coercive force Hc(2) of the ferromagnetic material layer in the negative magnetic field direction decreases to Hc(2) = (Hc - Ha), which actually makes the domain wall more likely to move and causes a shift error. Here, the coercive forces Hc(1) and Hc(2) of the ferromagnetic material layer in the magnetic field direction in Figure 4(b) are coercive forces observed under the influence of an external magnetic field due to adjacent magnetic phases, and are not the intrinsic coercive force of the magnetic layer 4. Excluding the influence (shift amount) Ha of the bias magnetic field Ha due to the magnetic layer, the coercive forces Hc(1) and Hc(2) in Figure 4(b) are Hc in both the positive and negative magnetic field directions, and this Hc is the intrinsic coercive force. Furthermore, in Patent Document 3, the coercive force (intrinsic coercive force) of the ferromagnetic material layer adjacent to the nonmagnetic phase is Hc because there is no magnetic field based on the nonmagnetic phase. In Patent Document 3, the intrinsic coercive force of the ferromagnetic material layer is Hc and is the same in all regions.

[0027] Furthermore, when an antiferromagnetic region is provided adjacent to a ferromagnetic material layer (a magnetic material to be measured) as in Patent Document 4, a bias magnetic field Hb based on the antiferromagnetic region is applied to the ferromagnetic material layer, and therefore, when the magnetization-magnetic field of the ferromagnetic material layer is measured, the magnetization-magnetic field characteristic curve shifts in the positive direction of the magnetic field H on the horizontal axis by the magnitude of the magnetic field Hb based on the antiferromagnetic region, as in the case of Figure 4(b). In this case, too, the apparent coercivity of the region of the ferromagnetic material layer in contact with the antiferromagnetic region increases by Hc(1) = (Hc + Hb) in the positive magnetic field direction compared to the coercivity Hc of the region of the ferromagnetic material layer in contact with the insulating layer, but decreases by Hc(2) = (Hc - Hb) in the negative magnetic field direction. However, even in this case, the intrinsic coercivity Hc of the ferromagnetic material layer is the same, being Hc, in all regions of the ferromagnetic material layer.

[0028] Although the influence of an external magnetic field on the coercive force is shown in FIGS. 4(a) and 4(b), the same applies to the magnetic anisotropy field.

[0029] In the magnetic memory of the present disclosure, when it is stated that "the first region of the magnetic wire layer has a first threshold current density, and the second region of the magnetic wire layer has a second threshold current density," "the second threshold current density is greater than the first threshold current density," and "the first threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer necessary to move the domain wall in the magnetic layer in the first region, and the second threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer necessary to move the domain wall in the magnetic layer in the second region," the magnetic wire layer to which the above pulse current density is applied is the magnetic wire layer in the magnetic memory of the present disclosure, i.e., the magnetic wire layer in a state where adjacent material layers are adjacent, and the applied pulse current is the pulse current applied to the magnetic memory of the present disclosure (the magnetic wire layer in a state where adjacent material layers are adjacent) to shift the domain wall in the magnetic layer.

[0030] As for the threshold current density, in addition to the threshold current density based on the current applied to the magnetic memory (including the current shunted to adjacent material layers in the second aspect described later), as described above, a threshold current density based on the current flowing only in a specific region of the magnetic nanowire layer without considering the shunting to adjacent material layers can also be considered and measured (defined). In the first aspect, the current shunted to adjacent material layers can be ignored, and if ignored, the threshold current density becomes the same in both senses of the above two definitions of threshold current density, but in the second aspect, the threshold current density is not based on the current flowing in a specific region of the magnetic nanowire layer alone without adjacent material layers, but is strictly based on the current applied to the magnetic memory (including the current shunted to adjacent material layers in the second aspect described later).

[0031] In the present disclosure, the "current density of the current flowing in the magnetic wire layer (or magnetic body layer)" is a value obtained by dividing the current flowing in the magnetic wire layer (or magnetic body layer) by the cross-sectional area of ​​the magnetic wire layer (or magnetic body layer). In the present disclosure, when it is said that the "second threshold current density is greater than the first threshold current density," it means that when there is a deviation in the first threshold current density in a first region of the magnetic wire layer (or magnetic body layer) or the second threshold current density in the second region of the magnetic wire layer (or magnetic body layer) in one or more first regions or second regions, or when there is a deviation in the current flowing in the magnetic wire layer (or magnetic body layer) or the cross-sectional area of ​​the magnetic wire layer (or magnetic body layer), taking these deviations into consideration, "the minimum value among the deviations in the second threshold current density is greater than the maximum value among the deviations in the first threshold current density." However, in the present disclosure, in practice, there is a significant difference between the second threshold current density and the first threshold current density, and the difference can be significant. Therefore, unless particularly necessary, it is acceptable to consider the current density and threshold current density as representative values ​​or average values. When discussing the current density and threshold current density below, deviation values ​​should be taken into consideration if necessary, but if not necessary, representative values ​​(average values) may be used. Here, the representative value may be a value obtained by measuring the current density and threshold current density using a general measurement method, but an average value may be used if necessary. Note that various numerical values ​​other than the current density and threshold current density in the present disclosure may be representative values, but an average value may be used if necessary. Here, the average value may be an average value of three or more measurements, three or more locations, or three or more measurements.

[0032] The current flowing through the magnetic nanowire layer (or magnetic layer) can be easily measured using a known current measurement method when the applied current flows only through the magnetic nanowire layer (or magnetic layer) in the measurement sample. When the applied current flows through both the magnetic nanowire layer (or magnetic layer) and the adjacent material layer in the measurement sample, the current can be calculated based on the measured current value from the sample and the electrical conductivity and cross-sectional area of ​​the magnetic nanowire layer (or magnetic layer) and the adjacent material layer. When the electrical conductivity of the magnetic nanowire layer (or magnetic layer) and the adjacent material layer cannot be measured directly, it can be known based on the material composition, and if necessary, the same material can be reproduced and the electrical conductivity of that material can be measured to determine the electrical conductivity. The cross-sectional area of ​​the magnetic nanowire layer (or magnetic layer) and the adjacent material layer can be determined by measuring the dimensions of the magnetic nanowire layer (or magnetic layer) and the adjacent material layer by SEM observation. If the current flowing through the magnetic wire layer (or magnetic layer) can be known, the current density at that time can be calculated from the cross-sectional area, and the threshold current density of the magnetic wire layer (or magnetic layer) can be measured as the lowest current density at which the domain wall moves by measuring whether or not the domain wall moves within the magnetic wire layer (or magnetic layer) while changing the applied current density. In the above, the measurement of the current flowing through the magnetic wire layer (or magnetic layer) can also be applied directly, or with necessary modifications, to the measurement of the current flowing through a specific region of the magnetic wire layer (or magnetic layer). For example, the electrical conductivity of a specific region of the magnetic wire layer (or magnetic layer) can be estimated by reproducing the material of that region and measuring its electrical conductivity.

[0033] <Magnetic Memory of the Present Disclosure> In a first aspect and a second aspect, the present disclosure provides a magnetic memory having a first direction and a second direction intersecting the first direction, comprising: a substrate; a magnetic wire layer including a magnetic layer or a magnetic layer and a spin Hall layer, and including a first region and a second region in the first direction as a data storage region; an adjacent material layer existing adjacent to the magnetic wire layer in the second direction and made of a non-magnetic material having no intrinsic magnetization, the adjacent material layer including a third region and a fourth region in the first direction, the third region existing in the second direction of the first region, and the fourth region existing in the second direction of the second region; and a circuit that applies a pulse current to the magnetic wire layer to move a domain wall in the magnetic layer in a direction from the first region toward the second region;a first material constituting the third region of the adjacent material layer and a second material constituting the fourth region are different materials from each other, and satisfy at least one of the following requirements A and B: A) the first material and the second material of the adjacent material layer are materials that can induce magnetic anisotropy in the magnetic layers of the first and second regions of the magnetic wire layer, and the intrinsic coercivity of the magnetic layer of the second region of the magnetic wire layer is greater than the intrinsic coercivity of the magnetic layer of the first region of the magnetic wire layer, or the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer of the second region of the magnetic wire layer is greater than the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer of the first region of the magnetic wire layer (Feature A); and B) the electrical conductivity of the fourth region of the adjacent material layer is higher than the electrical conductivity of the third region (Feature B). the first region of the magnetic wire layer has a first threshold current density, and the second region of the magnetic wire layer has a second threshold current density, wherein the first threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer necessary to move a domain wall in the magnetic layer in the first region, and the second threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer necessary to move a domain wall in the magnetic layer in the second region, and the second threshold current density is greater than the first threshold current density;

[0034] According to first and second aspects of the present disclosure, there is provided a 3D-magnetic nanowire magnetic memory which is a preferred embodiment of the magnetic memory, the magnetic memory comprising: a substrate having a surface including a third direction and a fourth direction intersecting each other, and a fifth direction perpendicular to the surface, the surface side of the substrate being an upper side in the fifth direction; the adjacent material layer on the substrate; and a first groove extending in the fifth direction from the adjacent material layer side toward a bottom surface of the substrate and in the fourth direction, the first groove having a first wall surface on one side in the third direction and a second wall surface and a bottom surface on the other side in the third direction; the adjacent material layer existing on at least both the first wall surface side and the second wall surface side of the first groove, the adjacent material layer including a first portion having the first wall surface and a second portion having the second wall surface, and the adjacent material layer including the third region and the fourth region aligned in the fifth direction in both the first portion and the second portion; The magnetic wire layer exists continuously from the first wall surface, through the bottom surface of the first groove, to the second wall surface, and a second groove extending in the fourth direction and the fifth direction exists between the magnetic wire layer on the first wall surface and the magnetic wire layer on the second wall surface; the magnetic wire layer includes a fifth region extending above the first portion of the adjacent material layer in the fifth direction, a sixth region extending above the second portion of the adjacent material layer in the fifth direction, and a seventh region on the bottom surface of the first groove; a write section is provided in the fifth region or the seventh region of the magnetic wire layer; a read section is provided in the seventh region of the magnetic wire layer; and a pair of wirings for applying a pulse current between the fifth region and the sixth region of the magnetic wire layer are also provided.

[0035] <<First Aspect (Form A)>> In a first aspect, the present disclosure provides a magnetic memory of the above-mentioned Form A, i.e., a magnetic memory characterized in that the coercivity of the magnetic layer in the second region of the magnetic wire layer is greater than the coercivity of the magnetic layer in the first region of the magnetic wire layer, or the product of the coercivity and magnetic anisotropy field of the magnetic layer in the second region of the magnetic wire layer is greater than the product of the coercivity and magnetic anisotropy field of the magnetic layer in the first region of the magnetic wire layer.

[0036] <First embodiment> Figure 2 schematically shows an example of a preferred three-dimensional magnetic nanowire memory according to the first embodiment of the magnetic memory based on the first aspect of the present disclosure. Figure 2 is a longitudinal cross-sectional view in a direction perpendicular to the surface of a substrate 2. In Figure 2, the direction of the surface of the substrate 2 is the X direction (in-plane direction, also simply referred to as the horizontal direction), and the direction perpendicular to the surface of the substrate is the Z direction (normal-to-plane direction, also simply referred to as the vertical direction).

[0037] 2 is a spin transfer torque (STT) type magnetic nanowire memory, and includes a substrate 2, a groove 3, a magnetic layer 4 as a magnetic nanowire layer 6, an adjacent material layer 7, wiring 8, a write member 9, and a read member 10. In the magnetic memory 1 of FIG. 2, the magnetic nanowire layer 6 is the magnetic layer 4. In the description of the first embodiment, the notation "magnetic layer 4" can be read as "magnetic nanowire layer 6."

[0038] The magnetic memory 1 has a groove 3 extending in a direction Z perpendicular to the surface of the substrate 2, and the groove 3 has wall surfaces 3a and 3b on both the left and right sides in the horizontal direction X, and a bottom surface 3c.

[0039] 2, the magnetic memory 1 has a magnetic layer 4 along the inner surface of the groove 3, i.e., along both wall surfaces 3a, 3b and bottom surface 3c. By forming the magnetic layer 4 in a three-dimensional perpendicular direction to the surface of the substrate 2, rather than in a two-dimensional in-plane direction, the storage capacity of the memory can be increased.

[0040] The magnetic layer 4 forms a single magnetic nanowire (with a U-shaped cross section) that continues from the left wall surface 3a of the groove 3, via the bottom surface 3c of the groove, to the right wall surface 3b, with this continuation direction as its length. The magnetic layer 4 may further have regions 4c and 4d that extend from the interior of the groove 3 to the left and right surfaces immediately above the surface of the substrate 2. The magnetic layer 4 has both end edges on the front and back sides of the paper in the drawing that define the width of the magnetic nanowire. In other words, the magnetic layer 4 on the left wall surface 3a of the groove 3 and the magnetic layer 4 on the right wall surface 3b are continuous via the magnetic layer on the bottom surface 3c of the groove, but are discontinuous on the front and back sides of the groove 3 in the drawing.

[0041] 2 , the write section and read section at the bottom of the groove 3 are preferably, but not limited to, located in the middle of the magnetic layer 4, and the magnetic layer 4 extends on both sides of the write section and read section regions, sandwiching or including the write section and read section regions. Multiple writes can be performed by repeatedly writing data to the magnetic layer 4 with the write section and then shifting the domain wall, for example, to the right. When the written data is shifted in the opposite direction (left) to read or rewrite it, the presence of the magnetic layer on the right side of the write section and read section prevents other data from being lost and allows the data to be retained. Furthermore, in the present disclosure, the magnetic layer 4 preferably has the same length on both sides of the write section and read section at the bottom of the groove 3. However, the 3D-magnetic memory structure of the present invention is easily manufactured because it is sufficient to form the magnetic layer 4 on both sides of the groove 3.

[0042] The material constituting the magnetic layer 4 is a ferromagnetic material, preferably a ferromagnetic material with perpendicular magnetization anisotropy, but may also be a ferromagnetic material with horizontal magnetization anisotropy. Examples of ferromagnetic materials include metals consisting of one or more of the 3d, 4d, 5d, 4f, and 5f elements, or compounds of such metals with one or more of N, P, O, and S, or any of group V and group VI elements. For example, simple metals such as Co, Fe, Ni, Mn, B, Si, Zr, Nb, Ta, Ru, Ir, Pt, Ga, Al, Pd, Tb, and Gd; binary alloys such as CoFe-based alloys, NiFe-based alloys, MnAl-based alloys, MnGe-based alloys, MnGa-based alloys, FePt-based alloys, CoCr-based alloys, FePt-based alloys, FePd-based alloys, and CoPt-based alloys; ternary alloys such as TbFeCo-based alloys, CoFeB-based alloys, and CoMnSi-based alloys; layered structure materials such as Ni / Co, Co / Pd, Pt / Co / Pd, Pt / Co / Pt, and Pd / Co / Pd; metal oxides such as iron oxide, chromium oxide, and ferrite; and non-oxidized metal magnetic materials such as metal nitrides. Also available are ferromagnetic semiconductors in which one or more 3d elements are added to a group IV, group II-V, or group I-VI semiconductor, such as InFeAs, GaFeSb, and InFeSb.

[0043] The magnetic layer 4 may be a single ferromagnetic layer, a ferromagnetically coupled ferromagnetic / non-magnetic multilayer film, an antiferromagnetically coupled ferromagnetic / non-magnetic multilayer film, etc. Examples of ferromagnetically coupled ferromagnetic / non-magnetic multilayer films include Co / Pt / Co, Co / Pd / Co, Co / Ni / Co, CoFeB / Ru / Co, and CoFeB / Ta / Co.

[0044] As described above, the magnetic layer 4 is only required to function as a magnetic layer as a whole, and may have some additional film for functional purposes, and the magnetic layer does not have to be made entirely of ferromagnetic material.

[0045] 2, the magnetic layer 4 includes a first region 4a and a second region 4b in the length direction of the magnetic layer 4 as a data storage region, and the first region 4a and the second region 4b are adjacent to each other, forming a 1-bit memory region. Generally, the magnetic layer 4 has a data storage region in which pairs of the first region 4a and the second region 4b are repeated in the length direction, thereby forming a multi-bit memory region.

[0046] In the magnetic memory 1 of the first embodiment, the magnetic wire layer 6 is the magnetic layer 4 and does not include a spin Hall layer, so the first region 4a and the second region 4b of the magnetic layer 4 are also the first region 6a and the second region 6b of the magnetic wire layer 6. Therefore, in the spin transfer torque (STT) type magnetic memory 1 of the first embodiment, the first region and the second region of the magnetic layer 4 are referred to as the first region 4a and the second region 4b, and do not necessarily refer to them as the first region 6a and the second region 6b of the magnetic wire layer 6. This also applies to the magnetic memories 1-3 of the third embodiment described later. However, in magnetic memory 1 and magnetic memory 1-3, even though they are written as the first region 4a and the second region 4b, the first region 4a and the second region 4b are also the first region 6a and the second region 6b of the magnetic wire layer 6, and can also be read as the first region 6a and the second region 6b of the magnetic wire layer 6.

[0047] As described above, the magnetic layer 4 may further have a region 4c extending from inside the groove 3 to the left surface 2a immediately above the surface of the substrate 2, and a region 4d extending to the right surface 2b immediately above the surface of the substrate 2.

[0048] In the magnetic memory 1 of the first embodiment, the magnetic layer 4 includes a first region 4a and a second region 4b, and the coercive force of the magnetic layer 4 in the second region 4b of the magnetic layer 4 is greater than the coercive force of the magnetic layer 4 in the first region 4a, or the product of the coercive force and the magnetic anisotropy field of the magnetic layer in the second region 4b of the magnetic layer 4 is greater than the product of the coercive force and the magnetic anisotropy field of the magnetic layer in the first region 4a.

[0049] In this disclosure, for the sake of simplicity, the coercive force H ｃis the coercive force H of the first region 4a of the magnetic layer 4. ｃ or the coercive force H of the second region 4b (6b) of the magnetic layer 4 ｃ and magnetic anisotropy field H ｅｆｆ ｋ The product of these is the coercive force H of the first region 4a of the magnetic layer 4. ｃ and magnetic anisotropy field H ｅｆｆ ｋ The fact that "the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The product of these is expressed as the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ It is also written as "greater than the product of."

[0050] The minimum current density that must be applied to the magnetic layer 4 to move the domain wall in the magnetic layer 4 along the magnetic layer 4 is called the threshold current density J ｔｈ However, the threshold current density of the magnetic layer is the coercive force H of the magnetic material at the Bloch magnetic wall. ｃ and magnetic anisotropy field H ｅｆｆ ｋ is proportional to the coercive force H of the magnetic material at the Neel magnetic wall. ｃ It is known that the threshold current density is proportional to [J. Torrejon, Nat. Commun. (2014)]. Referring to Figure 3(a), when an upwardly magnetized magnetic domain (left side) and a downwardly magnetized magnetic domain (right side) are adjacent in a magnetic layer, as shown in the cross-sectional view at the top of the figure, there is a domain wall (a region where the magnetization direction rotates and reverses) at the boundary region between the two magnetic domains, as shown in the perspective view below. In a Bloch domain wall, the magnetic field direction rotates in a cross-section along the length of the magnetic layer, while in a Néel domain wall, the magnetic field direction rotates in a longitudinal section along the length of the magnetic layer. In a cross-tie magnetic wall, where Bloch and Néel domain walls are mixed, the threshold current density of a magnetic layer with a cross-tie magnetic wall is also proportional to the coercive force H of the magnetic material. ｃor coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ 3(b) and (c) show the coercive force H of a magnetic body (magnetic material). ｃ and magnetic anisotropy field H ｅｆｆ ｋ This is a graph that explains the H ｅｘｔ is the strength of the external magnetic field on the magnetic material, and R on the vertical axis Ｈ is the anomalous Hall resistance.

[0051] Whether the magnetic layer 4 forms a Bloch domain wall, a Néel domain wall, or a cross-tie domain wall is determined mainly by the material and manufacturing process of the magnetic layer 4, and particularly the film thickness of the magnetic layer 4 (the thickness of the magnetic layer), etc. Generally, Bloch domain walls are formed when the magnetic layer is thick, Néel domain walls are formed when the magnetic layer is thin, and cross-tie domain walls are formed when the magnetic layer is intermediate in thickness. Typically, Bloch domain walls and Néel domain walls are formed when the magnetic layer thickness reaches a boundary of, for example, about 400 Å. Therefore, considering current manufacturing processes, it is thought that Bloch domain walls will usually form in many magnetic nanowire memories.

[0052] In the first embodiment of the magnetic memory 1 of the present disclosure, the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ is the coercive force H of the first region 4a of the magnetic layer 4. ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ By making the threshold current density (second threshold current density) of the second region 4b of the magnetic layer 4 larger than the product of

[0053] If the first threshold current density of the second region 4b of the magnetic layer 4 is greater than the second threshold current density of the first region 4a of the magnetic layer 4, applying a first current density greater than the first threshold current density but less than the second threshold current density to the magnetic layer 4 will move the domain wall within the first region 4a but not within the second region 4b, so that the domain wall can be stopped in front of the second region 4b. To move the domain wall through and pass through the second region 4b, a second current density greater than the second threshold current density should be applied. Therefore, the coercive force H of the second region 4b ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The product of these is the coercive force H of the first region 4a. ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ In the magnetic memory 1 having a value larger than the product of the above, the domain wall can be stopped at an accurate position, so that shift errors can be prevented or reduced.

[0054] Furthermore, in the magnetic memory 1 of the present disclosure, the magnetic layer 4 (magnetic wire layer 6) can be flat to form magnetic layer regions having first and second threshold current densities. Therefore, even in a 3D-magnetic memory, it is possible to simply deposit a flat magnetic layer 4 on a flat substrate without using shape changes as in Patent Documents 1 and 2, thereby reducing process difficulty and costs. In a 3D-magnetic memory, the flat surfaces of the magnetic wire layer 6 and the adjacent material layer 7 described below refer to a level of flatness that can be formed using vertical etching (reactive ion etching) techniques, and can be substantially completely flat. Furthermore, the dimensions of the asperities of the entire region including the first and second regions in the thickness direction of the magnetic wire layer (the difference in the thickness direction dimensions of the first region and the second region) are smaller than the dimensions of each of the first and second regions in the depth direction of the groove (the length direction of the magnetic wire layer), preferably by half or less, or even by one-fifth or one-tenth or less.

[0055] Thus, according to the magnetic memory 1 of the present disclosure, it is possible to simultaneously reduce the process difficulty and cost and the shift error, and to realize a highly reliable 3D-magnetic nanowire memory.

[0056] In one preferred embodiment, the coercive force or the product of the coercive force and the magnetic anisotropy field of the magnetic layer 4 in the second region 4b may be 1.5 times or more, preferably 2 times or more, 5 times or more, 10 times or more, and even 100 times or more, larger than the coercive force or the product of the coercive force and the magnetic anisotropy field of the magnetic layer 4 in the first region 4a. According to the present disclosure, the difference in the coercive force or the product of the coercive force and the magnetic anisotropy field realized in the second region and the first region of the magnetic layer 4, and the difference between the second threshold current density and the first threshold current density based thereon, can be significantly and more remarkably larger than the difference in threshold current densities based on a shape change as in Patent Documents 1 and 2, which is another advantage of the present disclosure in addition to ease of manufacture.

[0057] In the present disclosure, the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The product of these is the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ It is possible to make the product larger than the product of (a) and (b) by selecting the materials for the third region 7a and the fourth region 7b of the adjacent material layer 7, which will be described later.

[0058] In the magnetic memory of the present disclosure (the same applies to the second embodiment and the following), the first region 4 a and the second region 4 b are preferably directly adjacent to each other in the longitudinal direction in the magnetic layer 4, and there is no need to include any additional regions other than these regions, except for necessary portions such as the write section, the read section, and the current application section. However, it is not excluded to include additional regions, as long as they do not impair the effect based on the threshold current densities of the first and second regions of the magnetic memory of the present disclosure, such as, for example, including one or more intermediate regions between the first region 4 a and the second region 4 b, which have a threshold current density intermediate between the threshold current density of the first region and the threshold current density of the second region, or including one or more additional regions following the first region and the second region, which have a threshold current density higher than the threshold current density of the second region. In the magnetic memory of the present disclosure (the same applies to the second embodiment and subsequent embodiments), the threshold current density of the first region 4a and the threshold current density of the second region 4b can be constant in each of the first region 4a and the second region 4b, which is preferable. However, even if the threshold current density of the second region varies, slopes, or changes in each region, it is sufficient that the threshold current density of the second region is higher than the threshold current density of the first region. Furthermore, even if the threshold current density continuously slopes from the first region 4a to the second region 4b, it is sufficient that the threshold current density of the second region is higher than the threshold current density of the first region. In the magnetic memory of the present disclosure (in both the first and second aspects), in the data storage area, the threshold current density (second threshold current density) of the second area 4b is higher than the threshold current density (first threshold current density) of the first area 4a of the magnetic layer 4 (magnetic wire layer 6), but when the magnetic layer 4 (magnetic wire layer 6) has a plurality of repeated first areas 4a, there is an area (for simplicity, hereinafter referred to as the fifth area) between adjacent first areas 4a whose threshold current density is lower than the threshold current density (first threshold current density) of the first area 4a, regardless of whether this is due to the direction of magnetization written as data.), shift errors can occur. Therefore, the gap between adjacent first regions 4a is required not to be a region (fifth region) with a threshold current density lower than the threshold current density (first threshold current density) of the first region 4a, regardless of whether it is due to the direction of magnetization written as data. However, in the magnetic memory of the present disclosure, it is possible to not include a fifth region, there is no reason to include a fifth region, and it is desirable not to include a fifth region, so the fifth region is usually not included. Even if, for special reasons or manufacturing defects or other reasons, there is an exceptional case in which the gap between adjacent first regions 4a is a fifth region in the data storage region, the number of such exceptional fifth regions is 5% or less, preferably 3% or less, 1% or less, 0.5% or less, 0.1% or less, or 0.01% or less, based on the total number of existing first regions 4a. In the present disclosure, the number of such fifth regions can be zero. Regarding the fifth region, in the first aspect of the present disclosure, the magnitude of the threshold current density of the magnetic layer 4 (magnetic nanowire layer 6) can be restated as the magnitude of the coercive force of the magnetic layer 4 or the product of the coercive force and the magnetic anisotropy field. However, when the magnetic nanowire layer is continuous with a region other than the data storage region, it is preferable that the same applies to the magnetic nanowire layer in the region other than the data storage region, but this is not necessarily the case for the magnetic nanowire layer in the region other than the data storage region.

[0059] In the present disclosure, when layers, regions, bands, etc. are referred to as "adjacent," it is preferable that the two layers, regions, or bands are in direct contact with each other and are arranged side by side, but an intermediate layer, region, or band may be interposed between the two layers, regions, or bands as long as the meaning of the two layers, regions, or bands being adjacent is not lost. Hereinafter, for simplicity, the term "adjacent" may be used, but this has the same meaning as above.

[0060] The dimensions of the magnetic layer 4 are not particularly limited, but typically, for example, the thickness is about 1-10 nm, preferably about 1-5 nm, the width is about 10-500 nm, preferably about 10-100 nm, and the length is about 1-100 μm or more, preferably about 10-100 μm or more. The above dimensions of the magnetic layer 4 are typical examples, and the dimensions of the magnetic layer 4 may be smaller or larger than these.

[0061] The lengthwise dimension of the first region 4a of the magnetic layer 4 need only be a dimension that allows stable magnetic domains to be formed, but is typically approximately equal to the width of the magnetic layer 4 and may be greater or less than that. The lengthwise dimension of the second region 4b of the magnetic layer 4 need only be capable of stopping the movement of the domain wall within the second region 4b, and may be, for example, at least one-hundredth, one-fiftieth, one-tenth, one-fifth, one-half, or more of the lengthwise dimension of the region 4a, or may even be equal to or greater than one time. However, the lengthwise dimension is preferably as short as possible, and may be, for example, at most one-half, one-fifth, or one-tenth of the lengthwise dimension of the region 4a, and more preferably at most one-tenth, one-twentieth, or more.

[0062] The first region 4a and the second region 4b of the magnetic layer 4 are repeated many times along the length of the magnetic layer 4, but in one preferred embodiment, a second region 4b having a high threshold current density may be present at the boundary between the memory region of the magnetic layer 4 (the repeated portion of the first region 4a and the second region 4b) and the fifth regions 4c and 4d of the magnetic layer 4 on the upper left and right surfaces 2c and 2d of the substrate 2, and at the boundary between the seventh region 4e of the magnetic layer 4 having the write member 9 and the read member 10 at the bottom 3c of the groove 3.

[0063] (Adjacent Material Layer) In the present disclosure, the adjacent material layer 7 is a non-magnetic layer made of a non-magnetic material, adjacent to the magnetic layer 4 in the thickness direction of the magnetic layer 4, and extending in the length direction of the magnetic layer 4 (magnetic nanowire layer 6). In particular, in the first aspect (form A), the adjacent material layer 7 is made of a material that can induce magnetic anisotropy, preferably perpendicular magnetic anisotropy, in the magnetic layer 4, and has a coercive force H ｃ or coercive force Hｃ and magnetic anisotropy field H ｅｆｆ ｋ The device is made of a material that can induce

[0064] In this disclosure, the adjacent material layer is made of a nonmagnetic material. In this disclosure, a nonmagnetic material is a nonmagnetic material in the sense that it does not apply a magnetic field bias to the adjacent magnetic nanowire. An antiferromagnetic material is not a nonmagnetic material in this disclosure because it has an internal antiferromagnetic interaction and applies a magnetic field bias to the magnetic nanowire. Ferromagnetic materials are generally classified as magnetic materials, but even ferromagnetic materials can have zero overall magnetization in the absence of an external magnetic field due to the magnetic domain structure within the ferromagnetic material. In such cases, the ferromagnetic material is considered a nonmagnetic material in this disclosure. However, ferromagnetic materials often have overall magnetization (intrinsic magnetization), or even if they do not have overall magnetization (intrinsic magnetization), they can be given magnetization (intrinsic magnetization) by aligning the magnetic domains, for example, by heat treatment under an external magnetic field. Therefore, if a material is made to have intrinsic magnetization by some method, it is considered a magnetic material in this disclosure and not a nonmagnetic material. On the other hand, paramagnetic materials and diamagnetic materials do not have any internal magnetization in the absence of an external magnetic field, so they are generally classified as nonmagnetic materials and are treated as nonmagnetic materials in this disclosure. In this disclosure, whether an adjacent material layer is nonmagnetic or not is determined by whether or not a magnetic field bias is applied to the magnetic nanowire. However, for simplicity, materials other than antiferromagnetic materials and ferromagnetic materials may also be used as nonmagnetic materials. In this disclosure, the term "nonmagnetic material" has the above definition unless otherwise specified or unless it is understood to have a different meaning from the context. In this disclosure, a nonmagnetic material in the sense of not applying a magnetic field bias to an adjacent magnetic nanowire, particularly a nonmagnetic material that does not have intrinsic magnetization, may also be simply referred to as a nonmagnetic material.

[0065] In the first aspect (Mode A) of the present disclosure, the difference in the coercivity or the product of the coercivity and the magnetic anisotropy field between the first and second regions of the magnetic layer 4 is based on the fact that the materials of the third and fourth regions of the adjacent material layer 7 are materials that can induce magnetic anisotropy in the magnetic layer 4 and are different from each other. Without being bound by theory, it is believed that the difference in the coercivity or the product of the coercivity and the magnetic anisotropy field between the first and second regions of the magnetic layer 4 is based on the difference in the crystal structure or crystal orientation between the first and second regions of the magnetic layer 4, and the difference in the crystal structure or crystal orientation between the first and second regions of the magnetic layer 4 is due to the influence of the materials of the third and fourth regions of the adjacent material layer.

[0066] In the first aspect of the present disclosure, the adjacent material layer 7 is preferably located on the substrate 2 side of the magnetic layer 4. This is because the magnetic anisotropy of the magnetic layer 4 is induced by the adjacent material layer 7, and the magnetic anisotropy of the magnetic layer 4 is manifested when the magnetic layer 4 is formed (deposited) on the adjacent material layer 7. While the magnetic layers can be formed of the same material, the adjacent material layer 7 must be formed of different materials in the third and fourth regions. Therefore, it is preferable that the adjacent material layer 7 is located on the substrate 2 side of the magnetic layer 4, as this facilitates manufacturing, particularly when fabricating a 3D device. However, if magnetic anisotropy can be induced in the magnetic layer 4 by, for example, forming the adjacent material layer 7 on the magnetic layer 4 and then performing an annealing treatment, the adjacent material layer 7 may be located on the opposite side of the substrate 2 from the magnetic layer 4.

[0067] 2, the adjacent material layer 7 is at least on the left side of the magnetic layer 4 (magnetic nanowire layer 6) on the left wall surface 3a of the groove 3, and also on the right side of the magnetic layer 4 on the right wall surface 3b of the groove 3. In Fig. 2, the adjacent material layer 7 is drawn as a layer along the magnetic layer 4 (magnetic nanowire layer 6), but it is sufficient that the adjacent material layer 7 has a thickness (dimension in the thickness direction of the magnetic nanowire layer) that is at least a certain amount greater than the thickness of the magnetic layer 4 (magnetic nanowire layer 6) (dimension in the X direction in the drawing), and it may extend in the horizontal direction of the drawing beyond the thickness shown in the drawing.

[0068] 2, the adjacent material layer 7 is adjacent to the magnetic layer 4, and thus is not limited thereto. As with the magnetic layer 4, the write section and read section at the bottom of the groove 3 are preferably located in the middle of the adjacent material layer 7, and the adjacent material layer 7 preferably extends to both sides of the write section and read section regions, sandwiching or including the write section and read section regions. In the magnetic memory of the present disclosure, the magnetic layer 4 and the adjacent material layer 7 are inseparable, particularly in the first region 4a and the second region 4b of the magnetic layer 4 and the third region 7a and the fourth region 7b of the adjacent material layer 7. However, after writing to the magnetic layer 4 with the write section, the domain wall is repeatedly shifted, for example, to the right, to perform multiple writes. When the written data is then shifted in the opposite direction (left) to read or rewrite the data, the presence of the magnetic layer on the right side of the write section and read section prevents other data from being lost and allows the data to be retained. In addition, in the present disclosure, it is preferable that the magnetic layer 4 and the adjacent material layer 7 have the same length on both sides of the write section and the read section at the bottom of the groove 3, but in the structure of the 3D-magnetic memory of the present invention, it is only necessary to form the adjacent material layer 7 and the magnetic layer 4 on both sides of the groove 3, so that it is easy to manufacture.

[0069] When a write member 9 or a read member 10 is provided on the magnetic layer 4 at the bottom of the groove 3, there may be an adjacent material layer adjacent to the magnetic layer 4 at the bottom of the groove 3 that is the same as the adjacent material layer 7 adjacent to the magnetic layer 4 in the first region or the second region, as shown in Fig. 2, but it is not necessarily the case that the adjacent material layer is the same. However, the presence of the adjacent material layer 7 (particularly the first material) or a material layer equivalent to the adjacent material layer 7 (particularly the first material) (underlying material capable of forming a magnetic layer) at least in the portion other than the write member 9 or the read member 1 means that the magnetic layer 4 at the bottom of the groove 3 has the same or equivalent coercive force H as that of the first region in particular. ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋFurthermore, if necessary, in the region below the magnetic layer 4 where the write member 9 or the read member 10 is present, an adjacent material layer 7 (particularly the first material) or a material layer equivalent to the adjacent material layer 7 (particularly the first material) may be present, for example thinly, between the magnetic layer 4 and the write member 9 or the read member 10.

[0070] The adjacent material layer 7 has a third region 7a made of a first material and a fourth region 7b made of a second material, and the third region 7a and the fourth region 7b are adjacent to each other in the lengthwise direction of the magnetic layer 4 and are repeatedly present in the perpendicular direction. Here, the term "adjacent" has the same meaning as described above for the regions of the magnetic layer 4. The third region 7a and the fourth region 7b are typically layers that are formed by deposition in the perpendicular direction of the substrate 2 before forming the groove 3, and may be present symmetrically on both the left and right sides of the groove 3 after the groove 3 is formed. In FIG. 2, the third region 7a and the fourth region 7b are depicted as being repeated twice, but they are usually formed more times.

[0071] In the thickness direction of the magnetic layer 4 (magnetic nanowire layer 6), the third region 7a of the adjacent material layer 7 is adjacent to the first region 4a of the magnetic layer 4 (first region 6a of the magnetic nanowire layer 6), and the fourth region 7b of the adjacent material layer 7 is adjacent to the second region 4b of the magnetic layer 4 (second region 6b of the magnetic nanowire layer 6). The adjacent material layer 7 in the first embodiment is a material that can induce the coercive force or the coercive force and a magnetic anisotropy field of the magnetic layer 4. The first region 4a and the second region 4b of the magnetic layer 4 have a coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋis a characteristic induced and defined by the first material of the third region 7a and the second material of the fourth region 7b of the adjacent material layer 7 adjacent to the first region 4a and the second region 4b. Furthermore, the first region 4a and the second region 4b of the magnetic layer 4 (magnetic nanowire layer 6) are substantially regions adjacent to the third region 7a and the fourth region 7b of the adjacent material layer 7, and are therefore regions defined by the third region 7a and the fourth region 7b of the adjacent material layer 7.

[0072] The adjacent material layer 7, particularly on the first side, is a material that can induce the coercive force or the coercive force and a magnetic anisotropy field of the magnetic layer 4, but is different from the material (first material) that constitutes the third region 7a and the material (second material) that constitutes the fourth region 7b. The inventor has discovered that when a magnetic layer 4 (magnetic nanowire layer 6) is formed (particularly deposited and grown) on an adjacent material layer 7, the magnetic properties (parameters) including the coercivity and magnetic anisotropy field of the magnetic layer 4 differ depending on the material of the adjacent material layer 7, and that by appropriately selecting the materials of the non-magnetic third region 7a and fourth region 7b, the parameters of the coercivity and magnetic anisotropy field of the magnetic layer 4 formed adjacent to the third region 7a and fourth region 7b can be controlled, and the coercivity or the product of the coercivity and the magnetic anisotropy field can be made significantly larger in the second region 4b than in the first region 4a, and in a preferred embodiment, by more than one order of magnitude, and as a result, the threshold current density of the magnetic layer 4 (magnetic nanowire layer 6) can be made significantly, even dramatically, larger in the second region 4b than in the first region 4a, and the shift error of the magnetic nanowire memory can be dramatically improved.

[0073] Figure 5(a) shows the coercive force H of the magnetic layer measured when a perpendicular magnetization layer of a Pt / Co / Pt laminated structure (also simply referred to as CoPt) was formed on top of GdOx, NiOx, MgO, and CrOx as examples of adjacent materials (underlayers). ｃ and the magnetic anisotropy field H ｅｆｆ ｋ 5A, the coercive force H of the magnetic layer varies depending on the type of non-magnetic material in the underlayer. ｃ The maximum difference is about 33 times, and the magnetic anisotropy field H ｅｆｆ ｋTherefore, when GdOx and CrOx are used as adjacent materials, the coercive force H of the magnetic layer adjacent to GdOx and CrOx is ｃ is about 33 times, and the coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The product of these two factors is approximately 132 times different, and the threshold current densities in the magnetic layer regions adjacent to GdOx and CrOx are also approximately 33 times different for a Néel domain wall and approximately 132 times different for a Bloch domain wall. Therefore, in the case of a magnetic nanowire with a Bloch domain wall, which is a typical example, by using GdOx for the third region of the adjacent material layer and CrOx for the fourth region, the threshold current density of the second region can be increased by up to two orders of magnitude or more relative to the threshold current density of the first region of the perpendicular magnetization layer of the magnetic layer, which is a Pt / Co / Pt laminated structure. Even in the case of a magnetic nanowire with a Néel domain wall, by using GdOx for the third region of the adjacent material layer and CrOx for the fourth region, the threshold current density of the second region can be increased by up to approximately 33 times, or one order of magnitude or more, relative to the threshold current density of the first region of the perpendicular magnetization layer of the magnetic layer, which is a Pt / Co / Pt laminated structure. Furthermore, when the magnetic nanowire has a cross-tie domain wall, it can be considered that the change occurs gradually between the two values ​​mentioned above.

[0074] In one preferred embodiment, by appropriately selecting the material of the adjacent material layer 7, the coercive force in the second region 4b of the magnetic layer 4 is preferably 1.1 times or more, 1.2 times or more, 1.3 times or more, 1.5 times or more, or 2 times or more, and more preferably 5 times or more, 10 times or more, 50 times or more, 100 times or more, 200 times or more, 300 times or more, or 1000 times or more, than the coercive force in the first region 4a of the magnetic layer 4. Furthermore, since a larger ratio is more preferable, there is no particular upper limit, but the ratio may be, for example, 10,000 times or less, 1000 times or less, 500 times or less, 300 times or less, 200 times or less, 150 times or less, 100 times or less, 20 times or less, 10 times or less, 5 times or less, 2 times or less, or the like. Furthermore, the product of the coercive force and the magnetic anisotropy field in the second region 4b of the magnetic layer 4 is preferably 1.1 times or more, 1.2 times or more, 1.3 times or more, 1.5 times or more, or 2 times or more, and more preferably 5 times or more, 10 times or more, 50 times or more, 100 times or more, 200 times or more, 300 times or more, 1000 times or more, or 1000 times or more, etc., of the product of the coercive force and the magnetic anisotropy field in the first region 4a of the magnetic layer 4. Furthermore, since a larger ratio is more preferable, there is no particular upper limit, and the product may be, for example, 50,000 times or less, 10,000 times or less, 1000 times or less, 500 times or less, 300 times or less, 200 times or less, 150 times or less, 100 times or less, 20 times or less, 10 times or less, 5 times or less, 2 times or less, etc. Here, the above ratio of 2 times or less, and further 10 times or less, is a significant effect in preventing shift errors during domain wall movement.

[0075] In one preferred embodiment, the lower limit of the coercivity of the first region of magnetic layer 4 depends on the coercivity and magnetic anisotropy field of the second region of magnetic layer 4, and may be large or small as long as magnetic anisotropy is exhibited, but may be, for example, 5 Oe or more, 10 Oe or more, 20 Oe or more, 50 Oe or more, 100 Oe or more, 200 Oe or more, 300 Oe or more, 400 Oe or more, 500 Oe or more, etc. The upper limit of the coercivity of the first region of the magnetic layer 4 depends on the coercivity and magnetic anisotropy field of the second region of the magnetic layer 4, but may be, for example, 1000 Oe or less, 8000 Oe or less, 600 Oe or less, 500 Oe or less, 400 Oe or less, 300 Oe or less, 200 Oe or less, 150 Oe or less, 100 Oe or less, 50 Oe or less, 30 Oe or less, 20 Oe or less, 10 Oe or less, 5 Oe or less, etc. The lower limit of the coercivity of the second region of magnetic layer 4 depends on the coercivity and magnetic anisotropy magnetic field of the second region of magnetic layer 4, and is not particularly limited as long as the coercivity of the second region of magnetic layer 4 or the product of the coercivity and the magnetic anisotropy magnetic field is greater than the coercivity of the first region of magnetic layer 4 or the product of the coercivity and the magnetic anisotropy magnetic field.For example, it may be 5 Oe or more, 10 Oe or more, 20 Oe or more, 50 Oe or more, 100 Oe or more, 200 Oe or more, 300 Oe or more, 400 Oe or more, 500 Oe or more, etc. The upper limit of the coercivity of the first region of the magnetic layer 4 depends on the coercivity and magnetic anisotropy field of the second region of the magnetic layer 4, but may be, for example, 1000 Oe or less, 8000 Oe or less, 600 Oe or less, 500 Oe or less, 400 Oe or less, 300 Oe or less, 200 Oe or less, 150 Oe or less, 100 Oe or less, 50 Oe or less, 30 Oe or less, 20 Oe or less, 10 Oe or less, 5 Oe or less, etc.

[0076] In one preferred embodiment, the lower limit of the magnetic anisotropy field of the first region of magnetic layer 4 depends on the coercivity and magnetic anisotropy field of the second region of magnetic layer 4, and may be large or small as long as magnetic anisotropy is exhibited, and may be, for example, 1 kOe or more, 2 kOe or more, 3 kOe or more, 4 kOe or more, 5 kOe or more, 6 kOe or more, 7 kOe or more, 8 kOe or more, 10 kOe or more, etc. The upper limit of the magnetic anisotropy field of the first region of magnetic layer 4 depends on the coercivity and magnetic anisotropy field of the second region of magnetic layer 4, and may be, for example, 100 kOe or less, 50 kOe or less, 20 kOe or less, 10 kOe or less, 8 kOe or less, 7 kOe or less, 6 kOe or less, 5 kOe or less, 4 kOe or less, 3 Oe or less, 2 kOe or less, 1 kOe or less, 0.5 kOe or less, etc. The lower limit of the magnetic anisotropy field of the second region of magnetic layer 4 depends on the coercivity and magnetic anisotropy field of the second region of magnetic layer 4, and is not particularly limited as long as the coercivity of the second region of magnetic layer 4 or the product of the coercivity and the magnetic anisotropy field is greater than the coercivity of the first region of magnetic layer 4 or the product of the coercivity and the magnetic anisotropy field.For example, it may be 1 kOe or more, 2 kOe or more, 3 kOe or more, 4 kOe or more, 5 kOe or more, 6 kOe or more, 7 kOe or more, 8 kOe or more, 10 kOe or more, 20 kOe or more, 30 kOe or more, etc. The upper limit of the magnetic anisotropy field of the first region of the magnetic layer 4 depends on the coercivity and magnetic anisotropy field of the second region of the magnetic layer 4, but may be, for example, 100 kOe or less, 50 kOe or less, 30 kOe or less, 20 kOe or less, 10 kOe or less, 8 kOe or less, 7 kOe or less, 6 kOe or less, 5 kOe or less, 4 kOe or less, 3 kOe or less, 2 kOe or less, 1 kOe or less, etc.

[0077] The graph in Figure 5(a) was obtained by the following experiment. The measurement sample was a cap layer / Pt (0.8 nm) / Co (0.8 nm) / Pt (0.8 nm) / adjacent material (buffer layer) / SiO , as shown in Figures 5(b) and 5(c). ２ The cap layer is Ta (1 nm) / MgAl in Fig. 5(b). ２ O ４ In Fig. 5(c), BiSb (10 nm) is used, and NiO is used as the adjacent material (buffer layer, underlayer) to the magnetic layer.ｘ (10 nm), CrO ｘ (10 nm), GdOx (10 nm), and MgO (10 nm) were used, and a layered structure of Pt (0.8 nm) / Co (0.8 nm) / Pt (0.8 nm) was used as the ferromagnetic material.

[0078] Coercive force H ｃ was measured by the following method. 1) A sample with the Hall bar shape shown in Figure 6(a) (stack: cap layer / CoPt / buffer layer (adjacent material) / thermal oxidation Si substrate) was prepared. 2) A direct current I was applied in the x direction. 3) The external magnetic field was swept in the z direction, and the Hall voltage Vxy generated in the y direction was measured to determine the anomalous Hall resistance (R ＡＨＥ = Vxy / I) 4) R ＡＨＥ Calculating the magnetic field (Hc) where θ = 0. The measurement results are shown in Figures 6(b) to 6(e).

[0079] magnetic anisotropy field H ｅｆｆ ｋ was measured by the following method. 1) A sample with the shape of a Hall bar shown in Figure 7(a) (stack: cap layer / CoPt / buffer layer (adjacent material) / thermal oxidation Si substrate) is prepared. 2) A direct current I is applied in the x direction. 3) The external magnetic field is swept in the x direction + δ (δ is a small angle measured from the x axis in the xz plane) while measuring the Hall voltage Vxy generated in the y direction, and the external magnetic field dependence of the anomalous Hall resistance is calculated. 4) R is calculated using the following formula. ＡＨＥ By fitting the magnetic field dependence of ｅｆｆ ｋ (The solid black line in the figure is the fitting curve) However, H ｅｘｔ << H ｅｆｆ ｋ The range in which ＡＨＥ H ｅｘｔ The fitting was performed within a range where the parameter changes parabolically with respect to the parameter . The measurement results are shown in Figure 7 (b) to (e).

[0080] Therefore, by appropriately selecting the first material constituting the third region 7a and the second material constituting the fourth region 7b of the adjacent material layer 7, the coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ and controlling the coercive force H of the second region 4b. ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The product of these is the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ and the threshold current density (second threshold current density) of the second region 4 b can be at least significantly, preferably significantly, or even dramatically greater than the product of (a) and (b). As a result, the threshold current density (second threshold current density) of the second region 4 b can be at least significantly, preferably significantly, or even dramatically greater than the threshold current density (first threshold current density) of the first region 4 a. If the second threshold current density of the second region 4 b of the magnetic layer 4 is at least significantly greater than the first threshold current density of the first region 4 a, then by applying a current having a current density intermediate between the first threshold current density and the second threshold current density to the magnetic layer 4, the domain wall moving in the first region 4 a of the magnetic layer 4 can be reliably stopped in the second region 4 b, thereby making it possible to prevent and reduce shift errors with greater precision.

[0081] In the present disclosure, the second threshold current density is greater than the first threshold current density, but the difference between the first threshold current density and the second threshold current density is preferably a significant value, so that even when taking into account the fluctuation range of the current density of the shift current and the deviation between the first threshold current density and the second threshold current density, the shift current can reliably be a current density intermediate between the first threshold current density and the second threshold current density. However, in the magnetic memory of the present disclosure, the difference between the first threshold current density and the second threshold current density can generally be significantly large, or even remarkably large, to the extent that it is not necessary to take into account the fluctuation range of the current density of the shift current or the deviation between the first threshold current density and the second threshold current density. Therefore, unless particularly necessary, the difference between the first threshold current density and the second threshold current density is sufficient if it is the following, based on a representative value (or average value) of the threshold current density. That is, although it is not generalized because it depends on the configuration and application of the magnetic memory, for example, the ratio (Jth-2 / Jth-1) of the second threshold current density (Jth-2) to the first threshold current density (Jth-1) is preferably 1.05 or more [(Jth-2 / Jth-1) ≧ 1.05], and more preferably 1.1 or more, 1.2 or more, 1.5 or more, or 2.0 or more, and may further be 5.0 or more, 10 or more, 50 or more, 100 or more, 200 or more, 500 or more, or 1000 or more. The larger the ratio (Jth-2 / Jth-1) of the second threshold current density to the first threshold current density, the more preferable it is, and there is no particular upper limit as long as it can be realized, but it may be, for example, 10,000 or less, 1,000 or less, 500 or less, 300 or less, 200 or less, 150 or less, etc. From the viewpoint of practical use, the difference between the first threshold current density and the second threshold current density is 0.5 MA / cm ２ It is preferable that the resistance is 1 MA / cm or more, and more preferably 1 MA / cm or more. ２ Above, 2 MA / cm ２ The larger the difference between the second threshold current density and the first threshold current density, the more preferable. There is no particular upper limit as long as it can be realized. It depends on the desired magnetic memory, but it is preferably 10 MA / cm or more. ２ It is preferably 5 MA / m or less, and more preferably 5 MA / m ２ Below, 3MA / cm ２ It may be the following, etc.

[0082] The electrical density of the current flowing through the third region 7a and the fourth region 7b of the adjacent material layer 7 can be calculated as follows. If the third region 7a of the adjacent material layer 7 is an electrical insulator, no current flows through it. Therefore, the amount of current flowing through the first region 4a of the magnetic layer 4 is the same as the amount of current flowing through the magnetic layer 4 (the amount of current applied to the magnetic layer 4 including the adjacent material layer 7). The ratio of the amount of current flowing through the second region 4b of the magnetic layer 4 to the amount of current flowing through the fourth region 7b of the adjacent material layer 7 is determined by the ratio of the product of the electrical conductivity and cross-sectional area of ​​the second region 4b of the magnetic layer 4 to the product of the electrical conductivity and cross-sectional area of ​​the fourth region 7b of the adjacent material layer 7. Therefore, by calculating these electrical conductivities and cross-sectional areas, the current density of the current flowing through each region can be calculated based on the amount of current applied to the magnetic layer 4 including the adjacent material layer 7 (the amount of current flowing through the first region 4a of the magnetic layer 4). The current density of the current flowing through each region can be calculated by dividing the amount of current flowing by the cross-sectional area of ​​the region. In the above, if the third region 7a of the adjacent material layer 7 has electrical conductivity, correction may be performed in the same manner as for the fourth region 7b. The cross-sectional dimensions of each region can be measured by SEM observation. The current density of the current flowing through each region of the magnetic layer 4 and the adjacent material layer 7 can be calculated using a commercially available electromagnetic field simulator (e.g., ANSYS or COMSOL).

[0083] That is, in the first aspect and the first embodiment of the present disclosure (the same applies to the second embodiment), the feature that "the coercivity of the magnetic layer formed in the second region 4b of the magnetic layer 4 is greater than the coercivity of the magnetic layer 4 formed in the first region 4a of the magnetic layer 4, or the product of the coercivity and the magnetic anisotropy field of the magnetic layer 4 formed in the second region 4b of the magnetic layer 4 is greater than the product of the coercivity and the magnetic anisotropy field of the magnetic layer 4 formed in the first region 4a of the magnetic layer 4, and the second threshold current density of the second region 4b of the magnetic layer 4 is greater than the first threshold current density of the first region 4a of the magnetic layer 4" can be understood as follows: This means that "the second threshold current density of the second region 4b of the magnetic layer 4 is greater than the first threshold current density of the first region 4a of the magnetic layer 4" based on the fact that the "second material constituting the fourth region 7b of the magnetic layer 4" is "a material that can induce the coercive force and magnetic anisotropy field of the magnetic layer 4" and further "is selected so that the coercive force of the magnetic layer 4 formed in the second region 4b of the magnetic layer 4 is greater than the coercive force of the magnetic layer 4 formed in the first region 4a of the magnetic layer 4, or so that the product of the coercive force and magnetic anisotropy field of the magnetic layer 4 formed in the second region 4b of the magnetic layer 4 is greater than the product of the coercive force and magnetic anisotropy field of the magnetic layer 4 formed in the first region 4a of the magnetic layer 4."

[0084] In the first aspect (form A) of the present disclosure, without being bound by theory, it is believed that the difference in the coercivity or the product of the coercivity and the magnetic anisotropy field between the first and second regions of the magnetic layer 4 is due to the difference in the crystal structure or crystal orientation between the first and second regions of the magnetic layer 4, and that the difference in the crystal structure or crystal orientation between the first and second regions of the magnetic layer 4 is due to the influence of the materials of the third and fourth regions of the adjacent material layer.

[0085] In the magnetic memory 1 disclosed herein, when the magnetic domain (domain wall) is moved (shifted), the movement of the magnetic domain (domain wall) can be forcibly stopped in the second region where the threshold current density is high. Therefore, even if there is variation in the magnetic layer 4 within the memory cell array or variation in the length direction of the magnetic layer 4 within each memory cell, shift errors caused by these can be prevented and reduced with higher accuracy.

[0086] Furthermore, in the magnetic memory 1 of the present disclosure, the adjacent material layer 7 underlying the deposition of the magnetic layer 4 (magnetic nanowire layer 6) can have a flat surface. Therefore, even in a 3D magnetic memory, grooves can be formed in the adjacent material layer 7 in the direction perpendicular to the surface using an established vertical etching (reactive ion etching) technique. Then, without utilizing shape changes as in Patent Documents 1 and 2, the magnetic layer 4 (magnetic nanowire layer 6) can simply be deposited on the surface of the adjacent material layer 7, which is preferably flat and does not change in dimension in the vertical direction. This reduces process difficulty and costs. In a 3D magnetic memory, the surfaces of the adjacent material layer 7 and the magnetic nanowire layer 6 (magnetic layer 4) do not change in dimension in the vertical direction (the surface is linear in a vertical cross section of the surface), and "preferably flat" refers to a shape that can be formed using a vertical etching (reactive ion etching) technique, preferably a plane, and can also be a substantially completely flat surface. In other words, the grooves and the surfaces of the adjacent material layer 7 and the magnetic nanowire layer 6 (magnetic layer 4) can have a linear or linear cross section perpendicular to the substrate. In a 3D magnetic memory, with regard to changes in the vertical dimensions of the surfaces of the adjacent material layer 7 and the magnetic wire layer 6 (magnetic layer 4) within the vertical groove, the difference (average value, or even maximum value) in the thickness direction dimension of the magnetic wire layer between the third region and the fourth region within the vertical groove, and the difference (average value or maximum value) in the thickness direction dimension of the magnetic wire layer between the first region and the second region, can each be smaller than the dimension in the depth direction of the groove (length direction of the magnetic wire layer) of each region, preferably less than half, or even less than one-fifth, or even less than one-tenth.

[0087] Thus, according to the magnetic memory 1 of the present disclosure, it is possible to simultaneously reduce the process difficulty and cost and the shift error, and to realize a highly reliable 3D magnetic nanowire memory.

[0088] The material constituting the adjacent material layer is a material that can induce magnetic anisotropy (intrinsic coercivity, intrinsic magnetic anisotropy field) in the magnetic layer, and is preferably an underlayer material that is effective for growing the magnetic layer 4, particularly a ferromagnetic layer having perpendicular anisotropy, and is selected from the underlayer material that is effective for growing the magnetic layer 4, particularly a ferromagnetic layer having perpendicular anisotropy, and that can induce the coercivity H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The product of these is the coercive force H of the first region 4a. ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The first and second materials are selected so that the coercive force H of the magnetic layer deposited on the underlayer can be controlled to be larger than the product of ｃ and magnetic anisotropy field H ｅｆｆ ｋ Although the parameter "coercivity H" has not necessarily been focused on as in the present disclosure, ｃ and magnetic anisotropy field H ｅｆｆ ｋ Since the parameter can be measured as described above, the coercive force H of the magnetic layer can be measured for any new underlayer candidate material not specifically disclosed in this disclosure. ｃ and magnetic anisotropy field H ｅｆｆ ｋ By measuring the above, the first material and the second material can be selected and used.

[0089] Materials capable of inducing magnetic anisotropy in a magnetic layer include, for example, metal oxides, metal nitrides, metal carbides, Group IV semiconductors, Group III-V semiconductors, Group II-VI semiconductors, Group I-VIII semiconductors, or combinations thereof. Specific examples of materials capable of inducing magnetic anisotropy in a magnetic layer are described below. Materials capable of inducing as high a magnetic anisotropy as possible in a magnetic layer are sought after, and research and development are ongoing. Therefore, based on the coercivity or the product of the coercivity and the magnetic anisotropy field of a magnetic layer when these or other materials are used as adjacent material layers, or by experimentally measuring the coercivity or the product of the coercivity and the magnetic anisotropy field of a magnetic layer by placing various materials adjacent to the magnetic layer, materials that produce a significant difference in the coercivity or the product of the coercivity and the magnetic anisotropy field can be selected and used as the first material constituting the third region and the second material constituting the fourth region of the adjacent material layer in the present disclosure. For example, the present disclosure has revealed that CrOx and the like can induce high magnetic anisotropy.

[0090] In one embodiment, the material constituting the adjacent material layer 7 may be an insulator such as MgO, GdOx, NiO, or CrOx.

[0091] In one preferred example, the adjacent material layer 7 may be made of, for example, MgO, GdOx, NiO, or the like as the first material, and CrOx as the second material.

[0092] In relation to the second aspect of the present disclosure, if there is a difference in electrical conductivity between the third region 7 a (first material) and the fourth region 7 b (second material), the current flowing through the magnetic nanowire layer 6 may be shunted to the adjacent material layer 7. However, in the adjacent material layer 7 in the first aspect of the present disclosure, it is sufficient that the electrical conductivities of the third region 7 a and the fourth region 7 b and the difference therebetween do not cancel out the effect of the first aspect of the present disclosure, i.e., the effect based on the coercivity of the magnetic layer or the product of the coercivity and the magnetic anisotropy field. Therefore, it is preferable that the electrical conductivities of the third region 7 a and the fourth region 7 b are close to each other, or that the electrical conductivity of the fourth region 7 b is higher than that of the third region 7 a, but this is possible without any problems. For example, if the oxides are both electrical insulators, or the electrical conductivities can be close to each other. Alternatively, the third region 7 a (first material) may be an electrical conductor, and the fourth region 7 b (second material) may be an electrical insulator or a non-electrical conductor. In the present disclosure, the adjacent material layer may satisfy both the requirement of Form B (second aspect) that there is a difference in electrical conductivity between the third region and the fourth region, and the requirement of Form A (first aspect) that there is a difference in coercivity of the magnetic layer or the product of the coercivity and the magnetic anisotropy field. Furthermore, in one preferred embodiment of the present disclosure, an adjacent material layer satisfying the requirements of Form A and an adjacent material layer satisfying the requirements of Form B may be provided adjacent to the magnetic nanowire layer on both sides of the magnetic nanowire layer.

[0093] In the adjacent material layer 7, the materials constituting each of the third region 7a and the fourth region 7b of the adjacent material layer 7 may preferably be the same and uniform. The fact that the materials constituting each of the third region 7a and the fourth region 7b of the adjacent material layer 7 may be the same and uniform simplifies the manufacturing process in that there is no need for complex control of the materials in the adjacent material layer 7, which is an advantage of the magnetic memory of the present disclosure. However, this does not exclude non-uniformity such as variations or gradients in the materials constituting each of the third region 7a and the fourth region 7b of the adjacent material layer 7, as long as the threshold current density of the magnetic nanowire layer 6 adjacent to the adjacent material layer 7 is within the range of the present disclosure in the first region 6a and the second region 6b. In other words, it is sufficient that the minimum threshold current density of the second region 6b of the magnetic nanowire layer 6 is greater than the maximum threshold current density of the first region 6a of the magnetic nanowire layer 6, and in this case, an intermediate region may be present as described above.

[0094] (Wiring for Applying Pulse Current) The magnetic layer 4 is connected to a pair of wirings 8a, 8b for applying a pulse current to the magnetic layer 4 in a fifth region 4c on the left surface 2a and a sixth region 4d on the right surface 2b of the substrate 2. In Fig. 2, a non-magnetic insulating material layer 7c, such as MgO, GdOx, or NiO, is interposed between the adjacent material layer 7 and each of the region 4c of the magnetic layer 4 on the upper left surface 2a and the region 4d of the magnetic layer 4 on the upper right surface 2b of the substrate 2. As described above, if the adjacent material layer 7 extends horizontally in the figure, the non-magnetic insulating material layer 7c may also be extended as needed between the magnetic layer 4, the wirings 8a, 8b, and the adjacent material layer 7 on the substrate 2.

[0095] The third region 7a and the fourth region 7b of the adjacent material layer 7 are formed repeatedly many times along the length direction of the magnetic layer 4, but it is preferable that the second region 4b having a high threshold current density is present at the boundary between the memory region of the magnetic layer 4 (the repeated portion of the first region 4a and the second region 4b) and the fifth region 4c of the magnetic layer 4 on the upper left and right surfaces 2c and 2d of the substrate 2, and at the boundary between the seventh region 4e of the magnetic layer 4 having the write member 9 and the read member 10. Therefore, in one preferred embodiment, the adjacent material layer 7 adjacent to the second region 4b at the boundary is the fourth region 7b (second material).

[0096] Since it is desirable that the portion of the magnetic layer 4 at the bottom 3c of the groove 3 be a magnetic layer having the same or equivalent magnetic properties as the magnetic layer 4, particularly the first region 4a, it is preferable that the portion adjacent to the magnetic layer 4 at the bottom 3c of the groove 3, at least the region where the read member 9 and write member 10 are not present, be composed of an adjacent material layer 7 (particularly the first material), and if necessary, a thin adjacent material layer 7 (particularly the first material) may be inserted between the magnetic layer 4 and the read member 9 and / or write member 10. For example, see FIG. 8.

[0097] The adjacent material layer 7 is adjacent to the magnetic layer 4 in the thickness direction of the magnetic layer 4, and between the magnetic layer 4 and the adjacent material layer 7, the magnetic properties and crystallinity of the magnetic layer 4 can be improved, and the coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ In this case, the intermediate layer may be considered to be included in the adjacent material layer 7, or the intermediate layer may be considered to be a layer independent of the adjacent material layer.

[0098] (Writing Section) The writing member 9 may be provided in the seventh region 4 e of the magnetic layer 4 on the bottom surface 3 c of the groove 3 .

[0099] The configuration of the write section for the magnetic layer 4 is known. For example, Fig. 8(a) is a partial view showing the vicinity of the bottom of the groove 3 of a magnetic memory having the same configuration as Fig. 2, but the write section has a write member 9, which is a ferromagnetic material with an upward magnetic field, and wiring 8c for writing. The write section in Fig. 8(a) uses spin injection writing.

[0100] There are known examples of the configuration of the writing member 9 for injecting spins into the magnetic layer 4. The writing member 9 can inject spins by using, for example, a magnetic tunnel junction (MTJ).

[0101] 8 shows an example of the configuration of a write member 9 using spin injection. As shown in FIG. 8(a), the write member 9 is provided with respect to the magnetic layer 4, and has wiring 8c on the side of the write member 9 opposite the magnetic layer 4. Specifically, the write member 9 may have a laminated structure of a tunnel barrier film 9a and a single ferromagnetic film 9b as shown in FIG. 8(b), or a laminated structure of a tunnel barrier film 9a and a ferromagnetically coupled ferromagnetic (9b) / non-magnetic (9c) / ferromagnetic (9d) multilayer film as shown in FIG. 8(c), or a laminated structure of a tunnel barrier film 9a and an antiferromagnetically coupled ferromagnetic (9b) / non-magnetic (9c) / ferromagnetic (9b) multilayer film as shown in FIG. 8(d). The tunnel barrier film 9a may be made of, for example, MgO, MgAl ２ O ４ The non-magnetic film 9c may be made of Ru, Ta, W, Ir, Pt, Ni, etc. The ferromagnetic film may be made of Co, Fe, CoFe, CoFeB, CoMn, FeMn, etc.

[0102] Writing by spin transfer will be described with reference to Figures 9(a) and 9(b). Figure 9(a) shows how, when the write member 9 is magnetized upward, a pulse current is passed from the wiring 8c to the write member 9, forming a region (magnetic domain) with upward magnetization in the region 4A of the magnetic layer 4 adjacent to the write member 9 through spin transfer. Next, a shift current pulse is passed to move the magnetic domain (domain wall), moving the tip of the written magnetic domain 4A to the next fourth region 4B. At this time, the magnetic domain 4B (the old bit of information) disappears. Figure 9(b) shows the state at this time, with the magnetic domain 4A moving just before the second region 4b of the magnetic layer adjacent to the fourth region 7b on the right side of the figure. At this time, the read member 10 is present below the magnetic domain 4A, making it possible to confirm the orientation of the written magnetic domain.

[0103] Conversely, Figures 9(c) and (d) show the state when a pulse current is passed from the write member 9 toward the wiring 8c, forming a region (magnetic domain) with downward magnetization in the region of the magnetic layer 4 adjacent to the write member 9.

[0104] The lengthwise dimension of the seventh region 4e of the magnetic layer 4 formed at the bottom 3c of the groove 3 is not particularly limited, but in one embodiment of the present disclosure, although not shown, the seventh region 4e may have a structure in which the seventh region 4e is composed of a first region 4a having a length of one bit as a write section and a second region 4b interposed between the first region 4a and the read section, each having a length of one bit, for a total of two bits. With this structure, the magnetic domain (domain wall) between the write section and the read section can be moved by a normal shift pulse.

[0105] In the present disclosure, the seventh region 4e of the magnetic layer 4 formed at the bottom 3c of the groove 3 preferably has magnetic anisotropy (particularly coercivity or coercivity and magnetic anisotropy field) corresponding to that of the first region, and the longitudinal dimension of the seventh region 4e can be approximately the length of one bit, i.e., the length of the first region 4a, or the combined length of the first region 4a and the second region 4b, and is particularly preferably the length of the first region 4a. If the seventh region 4e has such dimensions, when data is simply moved, i.e., when magnetic domains are moved bit by bit, without writing or reading, a shift current pulse set based on the dimensions of the first region 4a and the second region 4b is applied, and there is no need to separately consider the length of the seventh region 4e. Furthermore, with such dimensions, the length of the seventh region 4e (the width of the bottom of the groove) can be made shorter than in the case of the two-bit length described above, thereby improving the integration density of the memory. However, if necessary, the length of the seventh region 4e can be set to a dimension other than the length of one bit by simply applying a corresponding shift current pulse, and therefore the dimension is not limited to the above dimensions.

[0106] In the present disclosure, it is clear that the seventh region 4e of the magnetic layer 4 formed on the bottom 3c of the groove 3 is not limited to the structure or length examples of the above-described embodiments.

[0107] In one aspect of the present disclosure, the seventh region 4e of the magnetic layer 4 includes a read member 9, a wiring 7c, and a write member 10. Generally, particularly when the seventh region 4e is approximately one bit long, the longitudinal dimension of the read member 9 is preferably at least half of one bit. From the viewpoint of the stability of the magnetic domains formed, it is desirable for the magnetic domains to be as large as possible. In this case, if the seventh region 4e is approximately one bit long, the longitudinal dimensions of the wiring 7c and the write member 10 in the seventh region 4e of the magnetic layer 4 may be less than half or less than half of one bit, but this is acceptable. The longitudinal dimensions of the wiring 7c and the write member 10 in the seventh region 4e of the magnetic layer 4 may generally be less than half or less than half of one bit.

[0108] Simulations confirmed that the lengthwise dimension of the read member 9 in the seventh region 4e of the magnetic layer 4 can be smaller than the length of the seventh region 4e or one bit. The simulations were performed using the Mumax3 simulator. Figure 10 illustrates the results of the simulations. In each figure in Figure 10, a first region (adjacent material GdOx) and a second region (adjacent material CrOx) are alternately present in the lengthwise direction x of the magnetic layer 4. In the figure, the direction and magnitude of magnetization are represented by color and shade of color in the simulation, but in the drawing they are converted to black and white grades. The +1 and -1 on the right side of the figure represent the direction and magnitude of magnetization.

[0109] First, the top diagram shows how a new magnetic domain is formed inside the first region (adjacent material GdOx) from the left after the write current pulse is applied. The time immediately after the magnetic domain is written is set as t = 0 ns. Next, a shift pulse (J １ = 0.7 x 10 １２ A / m ２ ) is applied, the magnetic domain moves to the right, and at t = 3.6 ns, the magnetic domain wall at the tip of the magnetic domain reaches the second region (adjacent material CrOx), but then the same shift pulse (J １ = 0.7 x 10 １２ A / m ２ ) continues to flow for, for example, t = 5.0 ns, the tip wall of the magnetic domain does not move at all.

[0110] Next, a depinning pulse (J ２ = 1.0 x 10 １２ A / m ２ When the shift pulse (J) is applied, the domain wall moves in the second region (adjacent material CrOx), so that the leading domain wall passes through the second region (adjacent material CrOx) and enters the second first region (adjacent material GdOx), but the domain wall at the rear end of the magnetic domain remains in the second region (adjacent material CrOx) (t = 7.0 ns), at which point the application of the depinning pulse is terminated. １ = 0.7 x 10 １２ A / m ２ When a voltage of t = 8.0 ns and t = 10.0 ns is applied, the leading edge of the magnetic domain moves to the right, but the domain wall at the trailing edge of the magnetic domain does not move, as can be seen in the figures for t = 8.0 ns and t = 10.0 ns.

[0111] Then, the shift pulse (J １ = 0.7 x 10 １２ A / m ２ As the voltage is applied, the domain wall at the tip of the magnetic domain reaches the second region (the adjacent material CrOx) and stops moving, as shown in the figure at t = 12.0 ns. At this final stage (t = 12.0 ns), the written magnetic domain expands to the length of one bit.

[0112] During the above current density application schedule, the domain walls of the previously written magnetic domains other than the newly written magnetic domains only move by one bit.

[0113] Furthermore, if the data written in the seventh region 4e of the magnetic layer 4 is the same as the data (magnetization direction) before writing, the data (magnetization direction) before writing does not change.

[0114] The above simulations confirmed that even if the longitudinal dimension of the read member 9 in the seventh region 4e of the magnetic layer 4 is smaller than the dimension of one bit or the seventh region 4e, the newly written magnetic domain can be expanded to the same length as the already written magnetic domain, that is, one bit.

[0115] 11 and 12(a) and (b) are examples of the spin transfer torque (STT) type, similar to FIGS. 2 and 8(a) and (b), and are magnetic memories having the same configuration as FIG. 2, but differ in that the writing method is a magnetic field application method, the writing member 9 is made of a non-magnetic, conductive material, and there is no need for a write wiring 8c separate from the writing member 9. Therefore, for the explanation of each part in FIG. 10, the explanation of each part in FIG. 2 can be directly referred to, except as follows.

[0116] 11 and 12(a) and (b), this writing is performed by applying a magnetic field. The configuration of the writing member 9 for applying a magnetic field is known. The writing member 9 for applying a magnetic field is made of a conductive member, and a magnetic field is generated by passing a current through the writing member 9, and writing is performed using that magnetic field.

[0117] 12( a), which shows a writing unit of the magnetic field application type, shows how a current is passed through the writing member 9 in a direction from the back to the front of the page to form a counterclockwise magnetic field around the writing member 9, thereby forming a region (magnetic domain) 4A having upward magnetization in region 4e of the magnetic layer 4 located to the upper right of the writing member 9. FIG. 12( b), which shows how a current is passed through the writing member 9 in a direction from the front to the back of the page to form a clockwise magnetic field around the writing member 9, thereby forming a region (magnetic domain) 4A having downward magnetization in region 4e of the magnetic layer 4 located to the upper right of the writing member 9.

[0118] 2 and 11, the read member 10 is connected to the seventh region 4f of the magnetic layer 4 at the bottom surface 3c of the groove 3. Examples of the configuration of the read member 10 relative to the magnetic layer 4 are known. The read member 10 can detect a difference in electrical resistance corresponding to the direction of magnetization of the magnetic layer 4, for example, by utilizing a magnetic tunnel junction (MTJ).

[0119] 13 shows an example of the configuration of the read member 10. As shown in FIG. 13(a), the read member 10 is provided with respect to the magnetic layer 4, and has a wiring 8d on the side of the read member 10 opposite the magnetic layer 4. Specifically, the read member 10 may have a laminated structure of a tunnel barrier film 10a and a single ferromagnetic film 10b as shown in FIG. 13(b), a laminated structure of a tunnel barrier film 10a and a ferromagnetically coupled multilayer film of a ferromagnetic material (10b) / a non-magnetic material (10c) / a ferromagnetic material (10d) as shown in FIG. 13(c), or a laminated structure of a tunnel barrier film 10a and an antiferromagnetically coupled multilayer film of a ferromagnetic material (10b) / a non-magnetic material (10c) / a ferromagnetic material (10b) as shown in FIG. 13(d). The tunnel barrier film 10a may be made of, for example, MgO, MgAl ２ O ４ The non-magnetic film 10c may be made of Ru, Ta, W, Ir, Pt, Ni, etc. The ferromagnetic film may be made of Co, Fe, CoFe, CoFeB, CoMn, FeMn, etc.

[0120] The information (magnetization direction) written in the magnetic layer 4 can be read by detecting the difference in the amount of current when a current is passed between the magnetic layer 4 and the wiring 8d, since the electrical resistance through the read member 10 varies depending on the magnetization direction in the seventh region 4e of the magnetic layer 4 adjacent to the read member 10. In this case, any of the wirings 8a, 8b, and 8c may be used as the opposing wiring (opposing electrode) of the wiring 8d, but the nearest wiring is preferable.

[0121] (Two-Dimensional Magnetic Memory) According to the present disclosure, it is clear that the magnetic memory of the first embodiment may be a two-dimensional magnetic memory instead of a three-dimensional magnetic memory. In a two-dimensional magnetic memory, a third region made of a first material and a fourth region made of a second material are formed as adjacent material layers on the surface of a substrate, and a magnetic layer is then formed thereon. Forming the third region made of a first material and the fourth region made of a second material as adjacent material layers on the surface of the substrate can be achieved, for example, by depositing a first material over the entire surface of the substrate, pattern-etching the region of the first material layer that will become the fourth region to a predetermined depth to form a groove in the fourth region, filling the groove with a second material, and then selectively removing the second material from areas other than the fourth region (within the groove).

[0122] (Driving Method) A driving method for domain wall motion in the magnetic memory 1 of the first embodiment will be described with reference to FIGS. 14A to 14F.

[0123] 14A(a), 14A(b) and 14B-14F(a) are schematic diagrams showing the storage portion of the magnetic memory of FIG. 2, particularly a portion of the magnetic layer 4 on the left side of the groove 3, with the vertical direction from bottom to top in FIG. 2 being shown from right to left in these figures. It should be noted that, in the method of driving domain wall motion, it is sufficient to consider the magnetic wire layer 6 as the magnetic wire layer 6, whether it includes only the magnetic layer 4 or the magnetic layer 4 and the spin Hall layer 5. In FIGS. 14A(a) and 14B-14F, the explanation of the driving methods for the magnetic memories 1 and 1-2 of the first and second embodiments is common, and it is sufficient to consider them as the magnetic wire layer 6, so the magnetic wire layer 6 is described as including the magnetic layer 4 and the spin Hall layer 5. In the following description of the method for driving domain wall motion in the magnetic memory 1 of the first embodiment, it is assumed that the magnetic nanowire layer 6 is only the magnetic layer 4 and that the spin Hall layer 5 is not present, and when referring to the magnetic layer 4, it means the magnetic nanowire layer 6 of the first embodiment. On the other hand, in the description of the method for driving domain wall motion in the magnetic memory 1-2 of the second embodiment described later, the magnetic nanowire layer 6 includes the magnetic layer 4 and the spin Hall layer 5, and the magnetic layer 4 and the spin Hall layer 5 together constitute the magnetic nanowire layer 6.

[0124] Here, because a method for driving domain wall motion in the magnetic memory 1 of the first embodiment will be described, it should be considered that the spin Hall layer 5 does not exist, even when referring to Figures 14A-14F. Therefore, when referring to the magnetic layer 4, the first region 4a of the magnetic layer 4, and the second region 4b of the magnetic layer 4, they mean the magnetic nanowire layer 6, the first region 6a of the magnetic nanowire layer 6, and the second region 6b of the magnetic nanowire layer 6, and can be read as the magnetic nanowire layer 6, the first region 6a of the magnetic nanowire layer 6, and the second region 6b of the magnetic nanowire layer 6.

[0125] In each of Figures 14A(a) and 14A(b) and Figures 14B-14F (hereinafter simply referred to as Figures 14A-14F, respectively), for example, if the third region 7a of the adjacent material layer 7 is made of GdOx, the fourth region 7b is made of CrOx, and the magnetic layer 4 is made of CoPt, the threshold current density (second threshold current density σ2) of the second region 4b (second region 6b) adjacent to the fourth region 7b of the magnetic layer 4 (magnetic nanowire layer 6) can be higher by two or more orders of magnitude than the threshold current density (first threshold current density σ1) of the first region 4a (first region 6a) adjacent to the third region 7a. 14A-14F, for the adjacent material layer 7, from left to right, i.e., from the writing member 9 to the reading member 10, the first (first) third region 7a and the first fourth region 7b are denoted as 7a-1 and 7b-1, respectively, and the next (second) third region 7a and fourth region 7b are denoted as 7a-2 and 7b-2, respectively. For the magnetic layer 4 (magnetic nanowire layer 6), although the boundary line between the first region and the second region is not shown, regions 4a-1, 4b-1, 4a-2, and 4b-2 (regions 6a-1, 6b-1, 6a-2, and 6b-2) are located directly above regions 7a-1, 7b-1, 7a-2, and 7b-2, respectively.

[0126] 14B-14F (hereinafter simply referred to as FIGS. 14B-14F, respectively) show pulse sequences of the driving current, with the horizontal axis representing time and the vertical axis representing current density. Here, the current density is the current density of the current applied to the magnetic layer 4 (magnetic nanowire layer 6) by the wiring 8a and wiring 8b.

[0127] 14B, the domain wall 11 is located in the first region 4a-1 of the magnetic layer 4 immediately above the first third region 7a-1, and the magnetization direction is downward to the left of that and upward to the right of that (see arrows). １ This current density (third current density J-3) is higher than the first threshold current density Jth-1 (GdOx) of the first region 4a but lower than the second threshold current density Jth-2 (CrOx) of the second region 4b (shift pulse). １ When a third current density J-3 is applied to the magnetic layer 4 in this state, the third current density J-3 is higher than the first threshold current density Jth-1 (GdOx), so the domain wall 11 can move to the right within the first first region 4a-1. However, because the third current density J-3 is lower than the second threshold current density Jth-2 (CrOx), the domain wall 11 cannot move within the first second region 4b-1 and stops at the position shown in Figure 14C (a), i.e., the position immediately before the first second region 4b-1 (the end of the first region 4a-1).

[0128] Time t １ If no current is passed through the magnetic layer 4 after this time has elapsed, the domain wall 11 will remain in the position shown in Figure 14C (a) (the end of the first region 4a-1), and the domain wall 11 will be maintained even if no current is passed through the magnetic memory, and the magnetic domain formed by the domain wall 11 (the written information in the first region 4a-1) will not be erased.

[0129] Next, when it is desired to shift the write information, first, the time t ２ At time t, a fourth current density J-4 is applied to the magnetic layer 4 (magnetic nanowire layer 6), and the fourth current density J-4 is higher than the second threshold current density Jth-2 (CrOx) of the second region 4b (depinning pulse). ２When a fourth current density J-4 is applied to the magnetic layer 4 (magnetic nanowire layer 6) at time t, the fourth current density J-4 is higher than the second threshold current density Jth-2 (CrOx), so the domain wall 11 moves within the first second region 4b-1, passes through the second region 4b-1, and can further enter the second first region 4a-2, and can move to the position shown in FIG. ２ is set to be short enough so that the domain wall 11 can pass through the first second region 4b-1 and remain to the left of the second first region 4a-2, without passing through the second first region 4a-2.

[0130] When you want to shift the write information, ２ Time t following ３ In this state, when a third current density J-3 is again applied to the magnetic layer 4 (magnetic nanowire layer 6), the domain wall 11 on the left side of the second first region 4a-2 moves within the second first region 4a-2 and stops just before the second second region 4b-2, as shown in Fig. 14F. In Fig. 14F, the domain wall 11-2 that could have been on the left side of the magnetic domain in the first first region 4a-1 in Fig. 14B is now at the end of the first first region 1a-1.

[0131] Therefore, at time t ２ and time t ３ By applying a series of current densities in the above, the domain wall 11 at the end of the first first region 4a-1 moves beyond the first second region 4b-1, moves within the second first region 4a-2, and stops at the end of the second first region 4a-2. In this way, the domain wall 11 at the end of the first first region 4a-1 moves (shifts) to the end of the second first region 4a-2, and the downward magnetic domain (written information, 1 bit of information) formed in the first first region 4a-1 can be shifted just enough to the second first region 4a-2, thereby preventing a shift error.

[0132] The above-mentioned movement of the domain wall 11 can be carried out in exactly the same manner even if the direction of the magnetic domain terminating at the domain wall 11 is downward instead of upward.

[0133] The above-described magnetic domain shift, i.e., the shift of one bit of information, can be repeated as many times as necessary to shift the desired number of bits. Therefore, the information (direction of the magnetic domain) at any one bit position in the magnetic layer 4 can be reliably shifted to the read member 10 without shift error, and can be read by the read member 10.

[0134] Conversely, when it is desired to shift the information in the second first region 4a-2 toward the writing member 9, that is, from the right side to the left side in the figure, in order to rewrite the information in the second first region 4a-2, by reversing the direction of the current applied to the magnetic layer 4 from that described above, the domain wall 11 at the end (right side) of the second first region 4a-2 can be moved toward the left side. Specifically, assuming that the domain wall 11 is at the end (right side) of the second first region 4a-2 and another domain wall 11-2 is at the end (right side) of the second first region 4a-2, first, a fourth current density J-4 is applied for a time t ２ When a third current density J-3 is applied, the domain wall 11 moves to the start (left end) of the second first region 4a-2 and stops just before the first second region 4b-1. Another domain wall 11-2 also moves to the start (left end) of the second first region 4a-2 and stops just before the second region to the left of that. Next, a third current density J-3 is applied for a time t ３ Then, the third current density J-3 is applied for a time t ３ By applying a voltage to move the domain wall 11 to the beginning of the first first region 4a-1, the downward magnetic domain (1-bit information) that was in the second first region 4a-2 can be shifted to the second first region 4a-2 without excess or deficiency, and shift errors at this time can be prevented. Then, by repeating this left shift of information, any 1-bit position (specific 1-bit position) in the magnetic layer 4 can be shifted to the write member 9, and new information (magnetic domain orientation) can be written to that specific 1-bit position in the write member 9. At this time, too, the movement of the domain wall and the magnetic domain is carried out without excess or deficiency, and shift errors are prevented.

[0135] Second Embodiment Figures 15-16 are schematic diagrams illustrating an example of a three-dimensional magnetic nanowire memory according to a second embodiment, which is a modification of the first embodiment of the magnetic memory of the present disclosure. While the first embodiment uses spin transfer torque (STT) type magnetic domain (domain wall) movement, the second embodiment uses spin orbit torque (SOT) type movement. In Figures 15-16, the same reference numerals are used for the same components as in Figures 2 and 11. Figures 15-16 are longitudinal cross-sectional views in a direction perpendicular to the surface of the substrate 2, where the direction of the surface of the substrate 2 is the X direction (in-plane direction, also simply referred to as the horizontal direction), and the direction perpendicular to the surface of the substrate 2 is the Z direction (perpendicular to the surface, also simply referred to as the vertical direction).

[0136] The magnetic memory 1-2 can have a configuration basically similar to that of the magnetic memory 1 shown in Figures 2 and 11, except that the magnetic nanowire layer 6 includes the spin Hall layer 5. Therefore, although repeated explanations will be omitted, it should be understood that the explanations and descriptions of the first embodiment with reference to Figures 2 and 11, etc., can be applied as is to this embodiment with reference to Figures 15-15, or can be applied with appropriate modifications.

[0137] 15-16 , the magnetic memory 1-2 of the second embodiment is a spin-orbit torque (SOT) type magnetic nanowire memory, and includes a substrate 2, a groove 3, a magnetic layer 4, a spin Hall layer 5, an adjacent material layer 7, wiring 8, a write member 9, and a read member 10. In the magnetic memory 1-2, the magnetic nanowire layer 6 includes the magnetic layer 4 and the spin Hall layer 5.

[0138] 15-16, the spin Hall layer 5 is formed on the opposite side of the magnetic layer 4 from the adjacent material layer 7, but it may also be formed on the same side of the magnetic layer 4 as the adjacent material layer 7, i.e., between the magnetic layer 4 and the adjacent material layer 7.

[0139] The spin Hall layer 5 is a functional layer that generates a pure spin current by utilizing the spin Hall effect caused by a current (electrons) flowing in the spin Hall layer 5, and injects this pure spin current into the magnetic layer 4 to move the domain wall in the magnetic layer 4. When a current (electrons) flows in the spin Hall layer 5, the spin Hall effect causes spins with different spin directions to accumulate in both directions perpendicular to the direction of the current (electrons) flow, generating a large pure spin current at the interface between the spin Hall layer 5 and the magnetic layer 4. When the pure spin current generated in the spin Hall layer 5 is injected into the magnetic layer 4 from the interface between the spin Hall layer 5 and the magnetic layer 4, the torque of the injected pure spin current can move the domain wall (magnetic domain) in the magnetic layer 4.

[0140] In the spin-orbit torque (SOT) type, by using a material for the spin Hall layer 5 with a spin Hall angle greater than 1, the torque of the pure spin current injected into the magnetic layer can be made greater than the torque based on the current. Also, since the thickness of the spin Hall layer 5 can be made greater than that of the magnetic layer 4, a larger current can be passed through the spin Hall layer 5 than through the magnetic layer 4. As a result of the combination of these factors, the driving force (torque) that moves the domain wall in the magnetic layer 4 is significantly greater due to the effect based on the current flowing through the spin Hall layer 5 than due to the effect based on the current flowing through the magnetic layer 4. As a result, the effect based on the spin Hall layer 5 is dominant in terms of the force that moves the domain wall in the magnetic layer 4, and the effect based on the magnetic layer 4 is negligible. In the spin-orbit torque (SOT) type, the magnetic wire layer 6 has the spin Hall layer 5 together with the magnetic layer 4, and for the reasons mentioned above, the driving force for moving the domain wall can be significantly increased by several times compared to the case of the spin transfer torque (STT) type in which only the magnetic layer 4 is used. Correspondingly, the threshold current density based on the driving current applied to the magnetic wire layer 6 can also be significantly reduced. For example, the domain wall can be moved even with a current density that is one order of magnitude smaller.

[0141] In the spin-orbit torque (SOT) type, the magnitude of the pure spin current generated by the spin Hall layer 5 is proportional to the current density passed through the spin Hall layer 5. The minimum magnitude of the pure spin current required for the pure spin current injected from the spin Hall layer 5 to the magnetic layer 4 to move the domain wall in the magnetic layer 4 is the coercive force H of the magnetic layer 4. ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ The threshold current density at which the current flowing through the magnetic layer 4 moves the domain wall in the magnetic layer 4 is also proportional to the product of the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ Therefore, in the spin-orbit torque (SOT) type, whether or not the domain wall in the magnetic layer 4 can be moved is determined by the sum of the current flowing through the spin Hall layer 5 and the current flowing through the magnetic layer 4, i.e., the current density of the current flowing through the magnetic wire layer 6. Therefore, the minimum current density that must be applied to the magnetic wire layer 6 to move the domain wall in the magnetic layer 4 along the magnetic layer 4 is defined as the threshold current density J of the magnetic wire layer 6. ｔｈ That is, the threshold current density J of the magnetic nanowire layer 6 ｔｈ is the coercive force H of the magnetic material for Bloch and cross-tie domain walls. ｃ and magnetic anisotropy field H ｅｆｆ ｋ and at the Néel domain wall, the coercivity H ｃ is proportional to.

[0142] Therefore, in the spin-orbit torque (SOT) type magnetic memory 1-2 of the second embodiment, the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋBy making the product of these values ​​larger in the second region 4b (second region 6b) than in the first region 4a (first region 6a), the threshold current density (second threshold current density) of the second region 6b of the magnetic wire layer 6 can be made larger than the threshold current density (first threshold current density) of the first region 6a of the magnetic wire layer 6, and shift errors can be prevented or reduced, as in the case of the spin transfer torque (STT) type magnetic memory 1 of the first embodiment.

[0143] The spin Hall layer 5 is preferably made of a material having a strong spin-orbit interaction that produces a strong spin Hall effect. For example, heavy metals such as W, Pt, and Ta, light oxides of heavy metals such as WOx and TaOx, BiSb, Bi ２ Se ３ The material can be a topological insulator such as YPtBi, or a topological semimetal such as YPtBi.

[0144] The thickness of the spin Hall layer 5 is determined taking into consideration the material and dimensions of the spin Hall layer 5, the magnitude of the net spin current to be injected into the magnetic layer 4, and the like, and may be, for example, 3-5 nm (for heavy metals such as W, Pt, and Ta), preferably 5-10 nm (for topological insulators such as BiSb and Bi2Se3), or even 10-20 nm (for topological semimetals such as YPtBi).

[0145] In the present disclosure, the magnetic wire layer 6 is collectively referred to as the magnetic wire layer 6, including the magnetic layer 4 and the spin Hall layer 5, and the adjacent material layer 7 is adjacent to the magnetic wire layer 6. In addition to the magnetic layer 4 and the spin Hall layer 5, the magnetic wire layer 6 may have additional layers or intermediate layers for some functional purpose, and the additional layers or intermediate layers may be located between the adjacent material layer 7.

[0146] 15-16, the first region 6a and second region 6b of the magnetic wire layer 6 are defined and defined by the third region 7a and fourth region 7b of the adjacent material layer 7. The first region 6a and second region 6b of the magnetic wire layer 6 are adjacent to the adjacent material layer in the thickness direction and are located at positions corresponding to the third region 7a and fourth region 7b of the adjacent material layer 7, respectively. The first region 6a and second region 6b of the magnetic wire layer 6 include the first region 4a and second region 4b of the magnetic layer 4 and the first region 5a and second region 5b of the spin Hall layer 5.

[0147] In the present disclosure, the domain wall-driving current is applied to the magnetic wire layer 6. In Figures 15-16, the wiring 8a and wiring 8b are connected to the magnetic wire layer 6, i.e., both the magnetic layer 4 and the spin Hall layer 5, and the domain wall-driving current is applied to both the magnetic layer 4 and the spin Hall layer 5.

[0148] (Writing Unit and Writing Method) Writing to the magnetic memory 1-2 of the second embodiment will be described. The magnetic memory 1-2 of the second embodiment is a spin-orbit torque (SOT) type, and is basically the same as the magnetic memory 1 of the first embodiment, except that it has a spin Hall layer 5. Therefore, the method of writing to the magnetic memory 1-2 of the second embodiment, the configuration of the writing unit, and the configuration of the writing member 9 may be the same as the method of writing to the magnetic memory 1 of the first embodiment, the configuration of the writing unit, and the configuration of the writing member 9, and the explanation of the method of writing to the magnetic memory 1 of the first embodiment, the configuration of the writing unit, and the configuration of the writing member 9, particularly the explanation with reference to Figures 8-12, can be directly referenced.

[0149] (Reading unit and reading method) The reading unit and reading method in the magnetic memory 1-2 of the second embodiment can be similar to those described for the reading unit and reading method in the magnetic memory 1 of the first embodiment, so the explanations of how to write to the magnetic memory 1 of the first embodiment, the configuration of the writing unit, and the configuration of the writing member 9, particularly the explanations referring to Figures 8-12, can be directly referred to.

[0150] (Driving Method) In the magnetic memory 1-2 of the second embodiment, as described above, the coercive force H ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ is multiplied by the coercive force H of the magnetic layer 4 in the first region 4a. ｃ or coercive force H ｃ and magnetic anisotropy field H ｅｆｆ ｋ and the threshold current density (second threshold current density) of the second region 6b of the magnetic nanowire layer 6 is made larger than the threshold current density (first threshold current density) of the first region 6a, thereby preventing and reducing shift errors in the magnetic nanowire memory, which is the same as the magnetic memory 1 of the first embodiment. Therefore, the driving method for the magnetic memory 1-2 of the second embodiment can be the same as that for the magnetic memory 1 of the first embodiment, and the driving method described with reference to Figures 14A to 14F can be used. Specifically, in the driving method described with reference to Figures 14A to 14F for the magnetic memory 1 of the first embodiment, the reference to the threshold current density of the magnetic layer 4 can be replaced with the reference to the threshold current density of the magnetic nanowire layer including the magnetic layer 4 and the spin Hall layer 5.

[0151] 14A-14F (a) already shows the spin Hall layer 5 as part of the magnetic wire layer 6 of the magnetic memory 1-2 of the second embodiment. In FIG. 14A (b) and each of FIG. 14B-14F (a), the first region 6a and the second region 6b of the magnetic wire layer 6, the first region 4a and the second region 4b of the magnetic layer 4, and the first region 5a and the second region 5b of the spin Hall layer 5 are not shown, but they are regions adjacent to and above the third regions 7a-1 and 7a-2 and the fourth regions 7b-1 and 7b-2 of the adjacent material layer 7, respectively.

[0152] Second Aspect (Configuration B) In the first aspect of the present disclosure, in the first and second embodiments, a magnetic memory (Configuration A) was described using a three-dimensional magnetic nanowire memory as an example, in which the coercivity of the magnetic layer 4 in the second region 6b (4b) is greater than the coercivity of the magnetic layer in the first region 6a (4a), or the product of the coercivity and magnetic anisotropy field of the magnetic layer 4 in the second region 6b (4b) is greater than the product of the coercivity and magnetic anisotropy field of the magnetic layer in the first region 6a (4a). In contrast, in the second aspect of the present disclosure, a magnetic memory (Configuration B) is provided in which the electrical conductivity of the fourth region 7b of the adjacent material layer is higher than the electrical conductivity of the third region 7a. As magnetic memories provided in the second aspect of the present disclosure, a magnetic memory 1-3 of the third embodiment and a magnetic memory 1-4 of the fourth embodiment are described as examples.

[0153] <Third and Fourth Embodiments> The configuration of a magnetic memory 1-3 of a third embodiment can be the same as that described for the magnetic memory 1 of the first embodiment, except for the material that constitutes the adjacent material layer 7, and reference can be made to Figures 2, 8 to 14. The configuration of a magnetic memory 1-4 of a fourth embodiment can be the same as that described for the magnetic memory 1-2 of the second embodiment, except for the material that constitutes the adjacent material layer 7, and reference can be made to Figures 2, 8 to 14, and 15 to 16.

[0154] The configurations of the magnetic memories 1-3 and 1-4 of the third and fourth embodiments, which are examples of the second aspect, differ from the magnetic memories 1 and 1-2 of the first and second embodiments, which are examples of the first aspect, in the material constituting the adjacent material layer 7, specifically, the requirements for the first material constituting the third region 7a and the second material constituting the fourth region 7b. Furthermore, as a result of the different materials constituting the adjacent material layer 7, the magnetic properties of the first region 4a and the second region 4b of the magnetic layer 4 of the second aspect may or may not differ from those of the first aspect. However, apart from the differences in the requirements for the first material constituting the third region 7a and the second material constituting the fourth region 7b of the adjacent material layer 7, the configurations of the magnetic memories 1-3 and 1-4 of the third and fourth embodiments basically refer to the description of the first aspect described above with reference to Figures 2, 8-14, 15-16, and these drawings, and therefore will not be repeated.

[0155] (Magnetic Layer) Similar to the first aspect (Mode A) of the present disclosure, the magnetic nanowire layer 6 (magnetic layer 4) in the second aspect (Mode B) of the present disclosure has a first region 6a (4a) and a second region 6b (4b) adjacent to a third region 7a and a fourth region 7b, respectively, of the adjacent material layer 7. In the first aspect, the second region of the magnetic layer is characterized in that the coercivity or the product of the coercivity and the magnetic anisotropy field is greater than the coercivity or the product of the coercivity and the magnetic anisotropy field of the magnetic layer in the first region, but in the second aspect, the magnetic anisotropy (coercivity or the product of the coercivity and the magnetic anisotropy field) of the first region and the second region of the magnetic layer may be the same or substantially the same, or may be different. In the second aspect, due to the difference in electrical conductivity between the third region and the fourth region of the adjacent material layer, more of the current flowing through the magnetic wire layer 6 (magnetic body layer 4) is diverted to the region of the adjacent material layer 7 with higher electrical conductivity, and as a result of the difference in current density flowing through the first region 6a (4a) and the second region 6b (4b) of the magnetic wire layer 6 (magnetic body layer 4), the effective threshold current density in the first region 4a and the second region 4b of the magnetic body layer 4 is different.

[0156] The magnetic layer in the second aspect may be a magnetic material capable of storing data and having magnetic anisotropy. Unlike the magnetic layer in the first aspect, the magnetic layer in the second aspect may have a different coercive force or a product of the coercive force and the magnetic anisotropy field between the first and second regions of the magnetic layer, and the coercive force or the product of the coercive force and the magnetic anisotropy field in the second region of the magnetic layer may be the same as the coercive force or the product of the coercive force and the magnetic anisotropy field in the first region of the magnetic layer, or the former may be larger or smaller than the latter. In the magnetic memory of the second aspect, regardless of the coercivity of the first and second regions of the magnetic layer or the product of the coercivity and the magnetic anisotropy field, the first and second regions of the adjacent material layer have different electrical conductivities, and the current is diverted to the second region of the adjacent material layer, thereby making the effective threshold current densities of the first and second regions of the magnetic nanowire layer (magnetic layer) different, and as defined above, the second threshold current density of the magnetic nanowire layer is greater than the first threshold current density.

[0157] In the second aspect, the configuration of the magnetic layer, such as the material and dimensions, may be the same as those described in the first aspect, or may be selected from those described in the first aspect. In the second aspect, although not limited thereto, it is preferable that the magnetic anisotropy (coercive force, magnetic anisotropy field) of the magnetic layer is large or can be made large.

[0158] (Adjacent Material Layer) In a second aspect of the present disclosure, the adjacent material layer 7 is adjacent to the magnetic wire layer 6 (magnetic body layer 4) in the thickness direction of the magnetic wire layer 6 (magnetic body layer 4) and extends in the length direction of the magnetic wire layer 6 (magnetic body layer 4). In the second aspect, the adjacent material layer 7 and the magnetic wire layer 6 (magnetic body layer 4) are both formed on the substrate 2, but the adjacent material layer 7 may be on the substrate 2 side, the opposite side to the substrate 2, or both the substrate 2 side and the opposite side to the substrate 2 with respect to the magnetic wire layer 6 (magnetic body layer 4).

[0159] In the second aspect of the present disclosure, the adjacent material layer 7 may be a material that can induce magnetic anisotropy in the magnetic body layer 4 of the magnetic wire layer 6, or a material that cannot induce magnetic anisotropy. When the adjacent material layer 7 is a material that can induce magnetic anisotropy in the magnetic body layer 4 of the magnetic wire layer 6, the adjacent material layer 7 satisfies the requirements of the second aspect (Mode B), but at the same time, it may or may not satisfy the requirements of the first aspect (Mode A). In particular, when the adjacent material layer 7 is on the substrate 2 side of the magnetic wire layer 6 (magnetic body layer 4), it is necessary or preferable that the adjacent material layer 7 be a material that can induce magnetic anisotropy in the magnetic body layer 4 of the magnetic wire layer 6. However, even in this case, the first material of the third region and the second material of the fourth region of the adjacent material layer 7 do not need to cause a difference in magnetic anisotropy between the first and second regions of the magnetic body layer 4, and they still do not need to cause a difference in magnetic anisotropy that satisfies the requirements of the first aspect (Mode A). Conversely, the magnetic anisotropy (coercive force, magnetic anisotropy field) of the second region of the magnetic layer 4 may be smaller than that of the first region due to the first material of the third region and the second material of the fourth region of the adjacent material layer 7. The adjacent material layer 7 in the second aspect of the present disclosure only needs to have a second threshold current density of the magnetic wire layer 6 (magnetic layer 4) greater than the first threshold current density as a result of the difference in electrical conductivity between the first material of the third region and the second material of the fourth region. Furthermore, in the present disclosure, an adjacent material layer 7 that satisfies the requirements of the second aspect may be present on one side of the magnetic wire layer 6, and at the same time, an adjacent material layer 7 that satisfies the requirements of the first aspect may be present on the opposite side of the magnetic wire layer 6.

[0160] In the second aspect of the present disclosure, the adjacent material layer 7 is made of a non-magnetic material. If the adjacent material layer 7 is not made of a non-magnetic material, that is, if it is made of a magnetic material, the leakage magnetic field from the adjacent material layer may affect it and cause a shift error in the domain wall motion of the magnetic nanowire layer. The meaning of the non-magnetic material is as defined above in relation to the first aspect.

[0161] In the magnetic memories 1-3 and 1-4 of the second aspect, third embodiment and fourth embodiment of the present disclosure, a third region 7a of the adjacent material layer 7 is adjacent to the first region 4a of the magnetic layer 4, and a fourth region 7b of the adjacent material layer 7 is adjacent to the second region 4b of the magnetic layer 4, and the electrical conductivity of the second material constituting the fourth region 7b of the adjacent material layer 7 is higher than the electrical conductivity of the first material constituting the third region 7a of the adjacent material layer 7.

[0162] The first and second materials of the adjacent material layer in the second aspect of the present disclosure may be selected from conductors and good conductors, and the first material may be selected from electrical insulators, as long as the electrical conductivity of the second material is higher than that of the first material. In one preferred embodiment, for example, the second material may be selected from conductors and good conductors, and the first material may be selected from electrical insulators. Generally, metals are good conductors, while metal oxides and metal nitrides are electrical insulators. Alternatively, the second and first materials may be selected from conductors and good conductors, with the electrical conductivities of the two materials being different. There are no particular restrictions on the insulating materials, conductors, or good conductors that can be used, as long as they can be used as components of a magnetic memory to form adjacent material layers and do not adversely affect other components. Examples of metals include noble metals such as Pt, Ru, and Au and their alloys; heavy metals such as Co, Ni, and Cu and their alloys; and refractory metals and alloys such as W and Ta. Examples of metals include n-Si, p-Si, Ge, GaAs, InP, GaN, SiC, SiGe, and CuInSe. ２ Semiconductors such as SiOx, GdOx, CrOx, WOx, TaOx, HfOx, and SiOx can also be used. Examples of electrical insulators include MgO, NiO, GdOx, CrOx, WOx, TaOx, HfOx, and SiOx. In the second aspect of the present disclosure, the adjacent material layer does not necessarily have to be a material capable of inducing magnetic anisotropy in the magnetic layer, but it can be a material capable of inducing magnetic anisotropy in the magnetic layer, and in one embodiment, it is preferably a material capable of inducing magnetic anisotropy in the magnetic layer. Materials capable of inducing magnetic anisotropy in the magnetic layer that are similar to those described in the first aspect can be used.

[0163] The first material may be any material having a lower electrical conductivity than the second material, but it is preferable that the difference in electrical conductivity between the first material and the second material be as large as possible (the former may be, for example, 2 / 3 or less, 1 / 2 or less, 1 / 10 or less, 1 / 100 or less of the latter), and it is particularly preferable that the first material be an electrical insulator (electrical conductivity is zero). Furthermore, the first material is preferably a material having an electrical conductivity lower than that of the magnetic nanowire layer, and it is more preferable that the difference in electrical conductivity between the first material and the magnetic nanowire layer be as large as possible (the former may be, for example, 2 / 3 or less, 1 / 2 or less, 1 / 10 or less, 1 / 100 or less of the latter), and it is particularly preferable that the first material be an electrical insulator (electrical conductivity is zero). Particularly preferred first materials include electrical insulators such as MgO, GdOx, NiO, and non-doped semiconductors such as Si and Ge. When the first material is used as a substrate (underlayer) for the magnetic nanowire layer, it is preferable that the first material is a material that can induce magnetic anisotropy in the magnetic nanowire layer and that can deposit a good magnetic nanowire layer. In this second aspect, the adjacent material layer being an electrically insulating material means that the electrical conductivity is 10 S / m or less, particularly zero.

[0164] The second material may have a higher electrical conductivity than the first material, but preferably has as large a difference in electrical conductivity as possible between it and the first material. The electrical conductivity of the second material may be preferably 1.1 times or more, 1.5 times or more, 2 times or more, one order of magnitude or more, or two orders of magnitude or more, relative to the electrical conductivity of the first material. However, if the first material is an electrical insulator, this multiplier may be infinite or close to it. Furthermore, the second material may have a smaller electrical conductivity than the magnetic nanowire layer, but preferably has an electrical conductivity equal to or more preferably higher than the electrical conductivity of the magnetic nanowire layer, and more preferably has as large a difference in electrical conductivity as possible between it and the magnetic nanowire layer (e.g., 1.0 times or more, 1.1 times or more, 1.3 times or more, 1.5 times or more, 2 times or more, 5 times or more, one order of magnitude or more, two orders of magnitude or more, etc.). In particular, good electrical conductors, particularly metals such as Pt, Ta, Ru, etc., and highly conductive semiconductors such as n-Si, p-Si, and other n-type or p-type semiconductors and compound semiconductors are preferably used. When the second material serves as the base material (underlayer) of the magnetic nanowire layer, it is preferable that it is a material that can induce magnetic anisotropy in the magnetic nanowire layer and that allows a good magnetic nanowire layer to be deposited.

[0165] The electrical conductivity of the first material and the second material of the adjacent material layer should be higher than that of the first material, so two types of materials can be selected from a wide range of materials such as insulators, conductors, and good conductors. It is preferable that the electrical conductivity of the first material of the adjacent material layer is as low as possible, and that of the second material is as high as possible. The electrical conductivity of an electrical insulator can be zero, but it can also be, for example, 10 ２ S / m or less, 10S / m or less, 10 ―１ On the other hand, the second material of the adjacent material layer preferably has as high an electrical conductivity as possible. For example, 10 ５ S / m~10 ６ It is preferable that the material has an electrical conductivity of about 10 S / m or more. ６ S / m or higher, and ７For example, highly conductive semiconductors such as Pt, Ta, and Ru can have electrical conductivities of 10 S / m or higher. ５ It has an electrical conductivity of S / m or more.

[0166] In one embodiment, the electrical conductivity of the first material and the second material of the adjacent material layer is preferably equal to or higher than the electrical conductivity of the magnetic layer. The electrical conductivity of the magnetic layer depends on the material of the magnetic layer, but is, for example, 10 ４ S / m~10 ６ S / m, especially 10 ５ S / m~10 ６ Therefore, it is preferable that the second material of the adjacent material layer has an electrical conductivity equal to or higher than the electrical conductivity of the magnetic layer. ４ S / m~10 ６ About S / m, 10 ５ S / m~10 ６ S / m or 10 ６ It is preferable that the electrical conductivity is about S / m or more.

[0167] The electrical conductivity of the first material and the second material of the adjacent material layer 7 can be measured, for example, by a four-terminal method. Since the electrical conductivity is known for each material, it can be estimated from a composition analysis of the material, or the electrical conductivity may be measured using a measurement sample that reproduces the same material.

[0168] The difference in electrical conductivity between the second region and the first region of the adjacent material layer is sufficient as long as the effective second threshold current density of the magnetic nanowire layer is greater than the first threshold current density. Furthermore, as mentioned above, based on the representative value (or average value) of the threshold current density, for example, the ratio (Jth-2 / Jth-1) of the second threshold current density (Jth-2) to the first threshold current density (Jth-1) is preferably 1.05 or more [(Jth-2 / Jth-1) ≧ 1.05], and more preferably 1.1 or more, 1.15 or more, 1.2 or more, 1.25 or more, 1.3 or more, 1.35 or more, 1.4 or more, 1.45 or more, 1.5 or more, 1.7 or more, 2.0 or more, and may be 5.0 or more, 10 or more, 20 or more, 50 or more, or 100 or more. The ratio of the second threshold current density to the first threshold current density (Jth-2 / Jth-1) is preferably as large as possible, and there is no particular upper limit as long as it can be realized, but it may be, for example, 100 or less, 50 or less, 20 or less, or 10 or less. From a practical viewpoint, it is also preferable that the difference between the first threshold current density and the second threshold current density is, for example, 0.5 MA / cm ２ It is preferable that the viscosity is 1 MA / cm or more, and more preferably 1 MA / cm or more. ２ Above, 2MA / cm ２ The larger the difference between the second threshold current density and the first threshold current density, the more preferable. There is no particular upper limit as long as it can be realized, but it is preferable that the upper limit is, for example, 10 mA / cm ２ It is preferable that the viscosity is 5 MA / cm or less, and more preferably 5 MA / cm or less. ２ Below, 3MA / cm ２ It may be the following, etc.

[0169] The electric density of the current flowing through the third region 7 a and the fourth region 7 b of the adjacent material layer 7 can be calculated as follows. If the third region 7 a of the adjacent material layer 7 is an electrical insulator, no current flows through it. Therefore, the amount of current flowing through the first region 4 a of the magnetic layer 4 is the same as the amount of current flowing through the magnetic layer 4 (the amount of current applied to the magnetic layer 4 including the adjacent material layer 7). The ratio of the amount of current flowing through the second region 4 b of the magnetic layer 4 to the amount of current flowing through the fourth region 7 b of the adjacent material layer 7 is determined by the ratio of the product of the electrical conductivity and cross-sectional area of ​​the second region 4 b of the magnetic layer 4 to the product of the electrical conductivity and cross-sectional area of ​​the fourth region 7 b of the adjacent material layer 7. Therefore, by calculating these electrical conductivities and cross-sectional areas, the current density of the current flowing through each region can be calculated based on the amount of current applied to the magnetic layer 4 including the adjacent material layer 7 (the amount of current flowing through the first region 4 a of the magnetic layer 4). The current density of the current flowing through each region can be calculated by dividing the amount of current flowing by the cross-sectional area of ​​the region. In the above, if the third region 7a of the adjacent material layer 7 has electrical conductivity, correction may be performed in the same manner as for the fourth region 7b. The cross-sectional dimensions of each region can be measured by SEM observation. The current density of the current flowing through each region of the magnetic layer 4 and the adjacent material layer 7 can be calculated using a commercially available electromagnetic field simulator (e.g., ANSYS or COMSOL).

[0170] Instead of the ratio between the second threshold current density and the first threshold current density, it can also be expressed by the rate of decrease of the current density flowing through the second region of the magnetic wire layer relative to the current density flowing through the first region, and the larger the rate of decrease of the current density of this magnetic wire layer, the more preferable it is, and it may be, for example, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, etc. Furthermore, since the larger the rate of decrease of the current density of this magnetic wire layer, the more preferable it is, it may be less than 100%, but it may be, for example, 99% or less, 98% or less, 95% or less, 90% or less, etc. Here, the ratio of the second threshold current density to the first threshold current density and the rate of decrease of the current density flowing through the second region of the magnetic nanowire layer relative to the current density flowing through the first region are valid for both the case where the magnetic nanowire is a magnetic layer (spin transfer torque (STT) type) and the case where the magnetic nanowire includes a magnetic layer and a spin Hall layer (spin orbit torque (SOT) type).

[0171] However, when the magnetic nanowire includes a spin Hall layer (spin-orbit torque (SOT) type), the current density through the spin Hall layer becomes important, so it may be preferable to express the current density as a ratio of the threshold current density or a reduction rate of the current density focusing on the current through the spin Hall layer. Furthermore, in the spin-orbit torque (SOT) type, the reduction rate of the current density near the interface between the spin Hall layer (SS) and the magnetic layer is more important than the reduction rate of the average current density throughout the spin Hall layer (SS). In the spin-orbit torque (SOT) type according to the second aspect of the present invention, the reduction rate of the average current density throughout the spin Hall layer (SS) may be, for example, 1% or more, 2% or more, 5% or more, 10% or more, 15% or more, 20% or more, or even 30% or more. The upper limit of this reduction rate can be determined taking into account constraints on device dimensions due to the increase in the thickness of adjacent material layers and constraints due to the drive current for domain wall motion, and may be, for example, 60% or less, 50% or less, 40% or less. Furthermore, the rate of decrease in current density near the interface between the spin Hall layer (SS) and the magnetic layer may be 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, etc. The upper limit of this rate of decrease can be determined taking into consideration constraints on device dimensions due to an increase in the thickness of adjacent material layers and constraints based on the drive current for domain wall motion, and may be, for example, 95% or less, 90% or less, 80% or less, 70% or less, etc.

[0172] In the second aspect of the present disclosure, the first and second materials of the adjacent material layer do not necessarily have to be those that cause a difference in the coercivity or the product of the coercivity and the magnetic anisotropy field of the magnetic layer induced by the adjacent material layer, as compared with the first aspect of the present disclosure, but may be those that cause a difference. It is preferable that the materials used for the adjacent material layer be those that can increase the difference in the coercivity or the product of the coercivity and the magnetic anisotropy field of the magnetic layer and also cause a difference in threshold current density based on current shunting. For example, the materials for the adjacent material layer may be selected from materials that cause the coercivity or the product of the coercivity and the magnetic anisotropy field of the magnetic layer to be close to each other, and the first material of the adjacent material layer may be an insulating material such as MgO or GdOx, and the second material of the adjacent material layer may be a metal such as W, Pt, Ru, or n++Si (concentration (e.g., 10E20 atoms / cc)).

[0173] The first material and the second material of the adjacent material layer 7 may not be a single material but may be a laminated structure of different materials. In one embodiment, the adjacent material layer 7 may have a laminated structure including an electrical insulator layer as the first material or a layer of a metal or the like as the second material, and a particularly thin layer of a material that can induce magnetic anisotropy, preferably perpendicular magnetic anisotropy, in the magnetic layer 4 interposed at the interface between the electrical insulator layer or the layer of metal, in particular, and the magnetic nanowire layer 7. In this case, the entire laminate structure of the electrical insulator layer or metal layer, the magnetic nanowire layer 7, and the material capable of inducing magnetic anisotropy, preferably perpendicular magnetic anisotropy, constitutes the adjacent material layer, and the entire laminate structure can induce magnetic anisotropy, preferably perpendicular magnetic anisotropy, in the magnetic layer 4, and the electrical conductivity of the fourth region 7b of the adjacent material layer 7 is higher than the electrical conductivity of the third region 7a of the adjacent material layer 7, contributing to the current shunting effect of the second aspect of the present disclosure, and the second threshold current density of the second region 4b of the magnetic layer 4 being higher than the first threshold current density of the first region 4a of the magnetic layer 4. Other laminate structures than those described above may also be used.

[0174] In the magnetic memories 1-3 and 1-4 of the second aspect and the third and fourth embodiments of the present disclosure, the electrical conductivity of the second material constituting the fourth region 7b of the adjacent material layer 7 is higher than the electrical conductivity of the first material constituting the third region 7a of the adjacent material layer 7, so that the second threshold current density of the second region 4b of the magnetic layer 4 can be made higher than the first threshold current density of the first region 4a of the magnetic layer 4. Therefore, the magnetic memories 1-3 and 1-4 have the characteristic that "the electrical conductivity of the fourth region 7b of the adjacent material layer 7 is higher than the electrical conductivity of the third region 7a of the adjacent material layer 7, and the second threshold current density of the second region 4b of the magnetic layer 4 is higher than the first threshold current density of the first region 4a of the magnetic layer 4."

[0175] In the second aspect of the present disclosure, the fact that "the second threshold current density of the second region 4 b of the magnetic layer 4 is higher than the first threshold current density of the first region 4 a of the magnetic layer 4" is based on the fact that "the electrical conductivity of the fourth region 7 b of the adjacent material layer 7 is higher than the electrical conductivity of the third region 7 a of the adjacent material layer 7," but since the difference in threshold current densities also depends on the thickness of the adjacent material layer 7, the thicker the adjacent material layer 7 is, the higher the second threshold current density can be compared to the first threshold current density. When the widths of the magnetic wire layer 6 and the adjacent material layer are the same, the current distribution effect is determined by the ratio of the product of the electrical conductivity and thickness of the fourth region of the adjacent material layer 7 to the product of the electrical conductivity and thickness of the third region of the adjacent material layer 7. In the second aspect, the effect can be obtained even if the thickness of the adjacent material layer 7 is less than 1 time the thickness of the magnetic nanowire layer 6 or the magnetic body layer 4, but preferably it may be 1 time or more, 1.5 times or more, 2 times or more, 3 times or more, 4 times or more, 5 times or more, 10 times or more, 15 times or more, 20 times or more, or even two or more orders of magnitude or more. The upper limit of the thickness of the adjacent material layer 7 is not particularly limited, but may be, for example, four or less orders of magnitude or less, three or less orders of magnitude or less, two or less orders of magnitude or less, or one or less orders of magnitude or less, of the thickness of the magnetic nanowire layer 6 or the magnetic body layer 4, taking into consideration constraints on the dimensions and integration density of the device.

[0176] 17(a) is a partial cross-sectional view of the laminated structure of the magnetic layer 4 and adjacent material layer 7 of a magnetic memory 1-3 according to one example of the third embodiment, and FIG. 17(b) is a partial schematic cross-sectional view of the laminated structure of the spin Hall layer 5, magnetic layer 4, and adjacent material layer 7 of a magnetic memory 1-4 according to the fourth embodiment. In the magnetic memory 1-3 of FIG. 17(b), the spin Hall layer 5 is located between the magnetic layer 4 and the adjacent material layer 7, but it may also be located on the opposite side of the magnetic layer 4 from the adjacent material layer 7, or on both sides of the magnetic layer 4. FIG. 17(c) shows an overall image of the laminated structure of the magnetic memory 1-4 according to the fourth embodiment shown in FIG. 15(b).

[0177] 17(a) and 17(b), the electrical conductivity of the second material in the fourth region 7b of the adjacent material layer 7 is higher than the electrical conductivity of the first material in the third region 7a. Therefore, in the magnetic memory 1-3 of the third embodiment shown in FIG. 17(a), the current flowing through the magnetic layer 4 is diverted to a greater extent in the fourth region 7b of the adjacent material layer 7 than in the third region 7a. Therefore, the current density of the current flowing through the magnetic layer 4 is smaller in the second region 4b of the magnetic layer 4 adjacent to the fourth region 7b of the adjacent material layer 7 than in the first region 4a adjacent to the first region 6a of the adjacent material layer 7. 17(b), the current flowing through the spin Hall layer 5 is also diverted to a greater extent in the fourth region 7b of the adjacent material layer 7 than in the third region 7a, so the current density of the current flowing through the spin Hall layer 5 is smaller in the second region 4b of the magnetic layer 4 adjacent to the fourth region 7b of the adjacent material layer 7 than in the first region 4a adjacent to the first region 6a of the adjacent material layer 7. That is, in the magnetic memory 1-4 of the fourth embodiment shown in FIG. 17(b), the current flowing through the magnetic layer 4 and the spin Hall layer 5 is diverted to a greater extent in the fourth region 7b of the adjacent material layer 7 than in the third region 7a, so the current density of the current flowing through the magnetic layer 4 and the spin Hall layer 5 is smaller in the second region 4b of the magnetic layer 4 adjacent to the fourth region 7b of the adjacent material layer 7 than in the first region 4a adjacent to the first region 6a of the adjacent material layer 7. In the magnetic memory 1-4 of the fourth embodiment, the current density of the current flowing through the spin Hall layer 5 has a dominant contribution to the movement of the domain wall in the magnetic layer 4, so the reduction and the rate of reduction of the current density of the current flowing through the spin Hall layer 5 are important.

[0178] Referring to Figure 17(a), in the magnetic memory 1-3 which is an example of the third embodiment, this is a spin transfer torque (STT) type, and the magnetic wire layer 6 does not include a spin Hall layer. However, the current density flowing in the magnetic layer 4 (magnetic wire layer 6) is smaller in the second region 4b adjacent to the fourth region 7b than in the first region 4a adjacent to the third region 7a. This means that the current density to be applied to the magnetic layer 4 (magnetic wire layer 6) (between the wirings 8a and 8b) in order to move the domain wall must be larger when moving the domain wall in the second region 4b than when moving the domain wall in the first region 4a. In other words, the effective threshold current density (second threshold current density) in the second region 4b (6b) of the magnetic layer 4 (magnetic wire layer 6) is greater than the effective threshold current density (first threshold current density) in the first region 4a (6a) of the magnetic layer 4 (magnetic wire layer 6).

[0179] 17(b), in the magnetic memory 1-4 as an example of the fourth embodiment, which is a spin-orbit torque (SOT) type, the current density flowing through the magnetic wire layer 6 including the magnetic layer 4 and the spin Hall layer 5 is smaller in the second region 6b adjacent to the fourth region 7b than in the first region 6a adjacent to the third region 7a. This means that the current density to be applied to the magnetic wire layer 6 (between the wirings 8a and 8b) to move the domain wall must be higher when moving the domain wall in the second region 4b of the magnetic layer 4 than when moving the domain wall in the first region 4a of the magnetic layer 4. In other words, the effective threshold current density (second threshold current density) in the second region 6b of the magnetic wire layer 6 is higher than the effective threshold current density (first threshold current density) in the first region 6a of the magnetic wire layer 6.

[0180] The magnetic memory 1-4 of the fourth embodiment is a spin-orbit torque (SOT) type. As described above with respect to the magnetic memory 1-2 of the second embodiment, the spin Hall layer 5 is a functional layer that generates a pure spin current by utilizing the spin Hall effect caused by a current (electrons) flowing in the spin Hall layer 5, and injects this pure spin current into the magnetic layer 4 to move the domain wall in the magnetic layer 4. When a current (electrons) flows in the spin Hall layer 5, the spin Hall effect causes spins with different spin directions to accumulate in both directions perpendicular to the direction of the current (electrons) flow, generating a large pure spin current along the interface between the spin Hall layer 5 and the magnetic layer 4. When the pure spin current generated in the spin Hall layer 5 is injected into the magnetic layer 4 from the interface between the spin Hall layer 5 and the magnetic layer 4, the torque of the injected pure spin current can move the domain wall (magnetic domain) in the magnetic layer 4.

[0181] In the spin-orbit torque (SOT) type, the driving force (torque) for moving the domain wall in the magnetic layer 4 is significantly greater due to the effect of the current flowing through the spin Hall layer 5 than due to the current flowing through the magnetic layer 4, and the effect due to the spin Hall layer 5 is dominant, with the effect due to the magnetic layer 4 also being negligible. In the spin-orbit torque (SOT) type, the magnetic wire layer has the spin Hall layer 5 as well as the magnetic layer 4, and for the reasons mentioned above, the driving force for moving the domain wall can be significantly several times larger than that in the spin-transfer torque (STT) type, which has only the magnetic layer. Correspondingly, the threshold current density based on the driving current applied to the magnetic wire layer can also be significantly reduced, and the domain wall can be moved even with a current density that is one order of magnitude smaller, for example.

[0182] For the above reasons, in the magnetic memory 1-4 of the fourth embodiment, it is possible to focus on the current density flowing in the spin Hall layer 5 and ignore for the time being the current density flowing in the magnetic layer 4. That is, since the threshold current density of the magnetic wire layer 6 (the minimum current density to be applied between the wirings 8a, 8b to move the domain wall in the magnetic layer 4) is predominantly determined by the current density flowing in the spin Hall layer 5, by making the fourth region 7b of the adjacent material layer 7 adjacent to the second region 6b of the magnetic wire layer 6 a good electrical conductor and the third region 7a adjacent to the first region 6a of the magnetic wire layer 6 an electrical insulator, more of the current to flow in the spin Hall layer 5 is diverted to the fourth region 7b of the adjacent material layer, the current density flowing in the spin Hall layer 5 can be made smaller in the region 5b adjacent to the second region 4b of the spin Hall layer 5 than in the region 5a adjacent to the first region 4a of the spin Hall layer 5. If the current density flowing through the spin Hall layer 5 becomes smaller, the net spin current injected from the spin Hall layer 5 into the magnetic layer 4, which moves the domain wall in the magnetic layer 4, also becomes smaller. Therefore, the minimum current density to be applied to the magnetic wire layer 6 (between the wirings 8a, 8b) to move the domain wall in the second region 6b of the magnetic wire layer 6 (the second region 4b of the magnetic layer 4), i.e., the effective threshold current density (second threshold current density σ2) of the second region 6b of the magnetic wire layer 6, becomes larger than the effective threshold current density (first threshold current density σ1) of the corresponding first region 6a of the magnetic wire layer 6.

[0183] In the above, the current density flowing through the spin Hall layer 5 was considered, ignoring the current density flowing through the magnetic layer 4. However, if the fourth region 7b of the adjacent material layer 7 adjacent to the second region 4b of the magnetic layer 4 is made a good electrical conductor and the third region 7a adjacent to the first region 4a is made an electrical insulator, the current density applied directly to the magnetic layer 4 from the wirings 8a, 8b will also be diverted more to the fourth region 7b of the adjacent material layer, as described above, so that the current density flowing directly through the magnetic layer 4 can be made smaller in the second region 4b than in the first region 4a. That is, even when only the current density flowing directly through the magnetic layer 4 is considered, the effective threshold current density in the second region 4b will be greater than the effective threshold current density in the first region 4a.

[0184] Therefore, in the magnetic memory 1-4 of the fourth embodiment, the threshold current density of the magnetic wire layer 6 can be considered as an additive combination of the threshold current density based on the spin Hall layer 5 and the threshold current density based on the magnetic layer 4. Therefore, in the magnetic memory 1-4 of the fourth embodiment, if the threshold current density of the current applied to the magnetic wire layer 6 is used as a reference, the current density applied to the magnetic wire layer 6 from the wirings 8a, 8b is determined in the same way as in the magnetic memory 1-3 of the third embodiment by making the electrical conductor of the fourth region 7b of the adjacent material layer 7 adjacent to the second region 6b of the magnetic wire layer 6 larger than the electrical insulator of the third region 7a adjacent to the first region 6a. This causes the current flowing in the magnetic wire layer 6 to be diverted more in the fourth region 7b of the adjacent material layer than in the third region 7a. This makes it possible to make the current density flowing in the magnetic wire layer 6 smaller in the second region 6b than in the first region 6a. As a result, the effective threshold current density (second threshold current density σ2) of the second region 6b of the magnetic wire layer 6 becomes larger than the effective threshold current density (first threshold current density σ1) of the first region 6a.

[0185] (Confirmation of effect in STT type) The results of an investigation using examples of materials constituting the magnetic layer 4 and adjacent material layer 7 are shown below. This shows that because the electrical conductivity of the second material constituting the fourth region 7b in the magnetic memory is higher than the electrical conductivity of the first material constituting the third region 7a of the adjacent material layer 7, the current density is lower in the second region 4b of the magnetic layer 4 adjacent to the fourth region 7b compared to the first region 4a of the magnetic layer 4 adjacent to the third region 7a.

[0186] When CoFeB is used as the magnetic layer (FM), insulating materials (MgO, GdOx) are used as the adjacent material layer (first material), and Ta, Pt, Ru, n++Si (concentration (10^20 particles / cc)) are used as the adjacent material layer (second material), the reduction rate of the current density in the magnetic layer was calculated using an electromagnetic field simulator (ANSYS or COMSOL). The results are shown in Figure 18 and Table 2.

[0187] According to Table 2, the current density reduction rate (%) of the magnetic layer is 55% to 87%. Therefore, if the current density reduction rate (%) of the magnetic layer is 55 to 87%, the ratio of the current densities before and after the current density reduction is 100:45-13 (the difference in current density is approximately 1.8 to 7.7 times), so the current densities of the domain wall-driving currents may be set relative to one another by setting the third current density J-3 shown in FIGS. 14B to 14F to a value intermediate between 13-45 and 100 (e.g., 60) and setting the fourth current density J-4 to a value exceeding 100 (e.g., 120), which makes it possible to sufficiently prevent and reduce shift errors.

[0188] (Confirmation of effect in SOT type) The electrical conductivity of the second material constituting the fourth region 7b of the adjacent material layer 7 in the magnetic memory is higher than that of the first material constituting the third region 7a of the adjacent material layer 7. As a result, the current density is lower in the spin Hall layer 5 in the second region 6b of the magnetic nanowire layer 6 adjacent to the fourth region 7b of the adjacent material layer 7 than in the adjacent spin Hall layer 5 in the first region 6a of the magnetic nanowire layer 6 adjacent to the third region 7a of the adjacent material layer 7. The results are shown below using examples of materials constituting the magnetic layer 4, spin Hall layer 5 and adjacent material layer 7.

[0189] CoFeB as the magnetic layer (FM), W and Bi as the spin Hall layer (SS) ２ Se ３ The current density reduction rate near the interface between the spin Hall layer (SS) and the magnetic layer and the average current density reduction rate throughout the spin Hall layer (SS) were calculated using an electromagnetic field simulator (ANSYS or COMSOL) for the cases where the first material layer (SS) was used and W, Pt, Ru, or n-Si (concentration (10^21 atoms / cc)) was used as the adjacent material layer (second material). The results are shown in Figure 19 and Table 3.

[0190] In Figure 19 and Table 3, because the SS current density near the adjacent material has a distribution in the film thickness direction, the current density at the SS / FM interface (within 1 nm of the interface), which contributes most to spin injection, is defined as the "SS current density at the SS / FM interface" (see Figure 19). The percentage decrease in the SS current density at the SS / FM interface near the adjacent material (second material) relative to the SS current density in the region where current shunting is negligible (the region where the adjacent material is an insulating material) is defined as the "SS current density reduction rate (%) at the SS / FM interface." Furthermore, the percentage decrease in the SS current density near the adjacent material (second material) relative to the SS current density in the region where current shunting is negligible (the region where the adjacent material is an insulating material) is defined as the "average SS current density reduction rate." In Figure 19 and Table 3, the adjacent material (second material) is simply referred to as the "adjacent material."

[0191] According to Table 3, the SS current density reduction rate (%) at the SS / FM interface was 21% to 60%, and the average SS current density reduction rate (%) was 12% to 26%.

[0192] In the spin Hall layer, the spin of the current (electrons) flowing within the spin Hall layer is polarized by the spin Hall effect, and pure spin (polarized spin) accumulates and increases at both end faces in the thickness direction. Therefore, the pure spin current is maximized at the interface between the spin Hall layer and the magnetic layer. Therefore, the current density that determines the movement of the domain wall when pure spin current is injected into the magnetic layer is the SS current density reduction rate (%) at the SS / FM interface, rather than the average SS current density reduction rate (%).

[0193] Therefore, based on the SS current density reduction rate (%) at the SS / FM interface, which contributes most to spin injection, the ratio of the current densities before and after the current density reduction is a maximum of 100:40 (the difference in current density is 2.5 times). Therefore, the current densities of the domain wall-driving currents can be set relative to each other by setting the third current density J-3 shown in FIGS. 14B to 14F to a value intermediate between 40 and 100 (e.g., 60) and the fourth current density J-4 to a value exceeding 100 (e.g., 120), which is sufficient to prevent and reduce shift errors. Even if the calculation is based on an average SS current density reduction rate (%) of 26%, the ratio of the current densities before and after the current density reduction is 100:74. Therefore, it is sufficient to set the current density of the domain wall-driving current to a value intermediate between 74 and 100 (e.g., 85) or a value exceeding 100 (e.g., 120) in relative ratio. Therefore, even if we consider the average SS current density reduction rate (%) as well, it is believed that it is possible to prevent or reduce shift errors.

[0194] From the viewpoint of the influence on the threshold current density of the magnetic layer, the current density reduction rate (%) of the magnetic layer (FM) is small compared to the SS current density reduction rate (%) at the SS / FM interface, as mentioned above, and can therefore be ignored. However, even when these are taken into consideration together, the influence of both current densities is additive, so there is no need to change the above conclusion, which was based on the SS current density reduction rate (%) at the SS / FM interface, and in fact it strengthens it.

[0195] (Driving Method) The driving method of the magnetic memories of the third and fourth embodiments may be similar to the driving method of the magnetic memories of the first and second embodiments, and reference can be made to FIGS. 14A to 14F.

[0196] <Third Aspect> <Method for Manufacturing Magnetic Memory> The present disclosure provides, as a third aspect, a method for manufacturing a magnetic memory. The method for manufacturing a magnetic memory of the present disclosure includes: providing an adjacent material layer made of a non-magnetic material on a substrate, the adjacent material layer including a third region and a fourth region in the first direction, wherein a first material constituting the third region and a second material constituting the fourth region of the adjacent material layer are different materials; forming a magnetic nanowire layer on the substrate, the magnetic nanowire layer including a magnetic layer or a spin Hall layer, the magnetic nanowire layer being adjacent to the adjacent material layer in the second direction and including a first region and a second region in the first direction, the first region existing in the second direction of the third region, and the second region existing in the second direction of the fourth region; wherein the adjacent material layer is selected from the following A and B: A) the first material and the second material of the adjacent material layer are materials that can induce magnetic anisotropy in the first region and the second region of the magnetic wire layer, and are selected so that the intrinsic coercivity of the magnetic layer in the second region of the magnetic wire layer is larger than the intrinsic coercivity of the magnetic layer in the first region of the magnetic wire layer, or the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer in the second region of the magnetic wire layer is larger than the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer in the first region of the magnetic wire layer (Feature A); and B) the electrical conductivity of the fourth region of the adjacent material layer is selected so that it is higher than the electrical conductivity of the third region (Feature B), and a circuit is provided that applies a pulse current to the magnetic wire layer to move a domain wall in the magnetic layer,a first region of the magnetic wire layer formed adjacent to the adjacent material layer having a first threshold current density, and a second region of the magnetic wire layer having a second threshold current density, wherein the first threshold current density refers to a minimum current density of the pulse current to be applied to the magnetic wire layer that is necessary to move a domain wall in the magnetic layer in the first region, and the second threshold current density refers to a minimum current density of the pulse current to be applied to the magnetic wire layer that is necessary to move a domain wall in the magnetic layer in the second region, and the second threshold current density is greater than the first threshold current density.

[0197] The present disclosure further provides, as a third aspect, a method for manufacturing a 3D-magnetic memory, and in a fifth embodiment, a method for manufacturing a 3D-magnetic memory comprising: a magnetic wire layer on a substrate, or a magnetic wire layer including a magnetic layer and a spin Hall layer; an adjacent material layer adjacent to the magnetic wire layer; and a circuit for applying a pulse current to the magnetic wire layer to move a domain wall in the magnetic layer, wherein a surface of the substrate includes eleventh and twelfth directions that intersect with each other, and a direction that intersects with the surface of the substrate is a thirteenth direction, and the method for manufacturing the 3D-magnetic memory comprises depositing a first band of a first material and a second band of a second material in the thirteenth direction as the adjacent material layer, and the first material and the second material are different materials; and the method for manufacturing the 3D-magnetic memory comprises: a surface of the substrate includes the eleventh and twelfth directions that intersect with each other, and the direction that intersects with the surface of the substrate is the thirteenth direction, depositing a first zone of the first material and a second zone of the second material in the thirteenth direction on the substrate as the adjacent material layer, the first material and the second material being different materials; forming a first trench in the adjacent material layer on the substrate, the first trench extending in the thirteenth direction and the twelfth direction from the adjacent material layer toward the substrate, the first trench being formed to penetrate the first zone and the second zone, so that in a vertical cross section including the eleventh direction and the thirteenth direction, the first trench has a first wall surface on one side of the first trench in the eleventh direction, a second wall surface on the other side, and a bottom surface, and a first portion of the adjacent material layer having the first wall surface on the one side of the first trench and a second portion of the adjacent material layer having the second wall surface on the other side of the first trench are formed; depositing the magnetic wire layer continuously extending from above the first portion of the adjacent material layer in the thirteenth direction, via the first wall surface of the adjacent material layer, the bottom surface of the first groove, and the second wall surface of the adjacent material layer, to above the second portion of the adjacent material layer in the thirteenth direction, and the deposited magnetic wire layer has a second groove extending in the thirteenth direction and a twelfth direction between the magnetic wire layer on the first wall surface and the magnetic wire layer on the second wall surface;when the substrate is viewed from the thirteenth direction, the magnetic wire layer has a third portion extending in the eleventh direction, and a fourth portion and a fifth portion which are present on both sides of the third portion in the twelfth direction and extend in the eleventh direction, and the third portion of the magnetic wire layer is isolated by selectively removing the fourth portion and the fifth portion of the magnetic wire layer.

[0198] Furthermore, as a sixth embodiment of the third aspect of the present disclosure, there is provided a method for manufacturing a magnetic memory according to the fifth embodiment, which satisfies at least one of the following requirements: the coercivity of the magnetic layer deposited on the second zone is greater than the coercivity of the magnetic layer deposited on the first zone, or the product of the coercivity and magnetic anisotropy field of the magnetic layer deposited on the second zone is greater than the product of the coercivity and magnetic anisotropy field of the magnetic layer deposited on the first zone (Mode A); and the electrical conductivity of the second zone of the adjacent material layer is higher than the electrical conductivity of the first zone (Mode B).

[0199] An example of a method for manufacturing a magnetic memory according to the fifth and sixth embodiments of the present disclosure will be described with reference to Figures 20A-20B. Although the structure of a three-dimensional magnetic nanowire memory has been disclosed in the past, a method for manufacturing a three-dimensional magnetic nanowire memory has not been specifically disclosed. Therefore, the present disclosure discloses a method for manufacturing a three-dimensional magnetic nanowire memory.

[0200] The structure and features of the magnetic memory magnetic nanowire memory in the fifth embodiment of the present disclosure may be as described in the first to fourth embodiments of the first aspect and the second aspect. Furthermore, the structure and features of the magnetic memory magnetic nanowire memory in the sixth embodiment of the present disclosure may be as described in the first to fourth embodiments of the first and second aspects. Therefore, although repeated description will be omitted, the description of the first and second aspects (first to fourth embodiments) can be referenced for the structure and features that the magnetic memory manufactured by the manufacturing method of the third aspect shares in common with the magnetic memories of the first and second aspects.

[0201] (Method for manufacturing a three-dimensional magnetic memory) Referring to FIG. 20A(a), a first material layer 22 and a second material layer 23 are sequentially and repeatedly deposited on a substrate 21. The first material layer 22 and the second material layer 23 correspond to the first and second zones, respectively, in the method for manufacturing the magnetic memory of the fifth embodiment described above, and are preferably layers for forming the third region 7a and the fourth region 7b of the adjacent material layer 7 in the magnetic memories 1, 1-2, 1-3, and 1-4 of the first to fourth embodiments. One in-plane direction of the substrate 21 is the X-direction. The direction perpendicular to the in-plane X-direction is the Y-direction, and the direction perpendicular to the surface of the substrate 21 is the Z-direction. The first material may be the material that constitutes the third region in the magnetic memories of the first to fourth embodiments, and the second material may be the material that constitutes the fourth region in the magnetic memories of the first to fourth embodiments.

[0202] 20A(b), the first material layer 22 and the second material layer 23 deposited on the substrate 21 are pattern-etched by a vertical etching method (reactive ion etching) to form slit-shaped grooves 24 extending in the Z and Y directions, and FIN structures 25 having a stacked structure of the first material layer 22 and the second material layer 23 are formed as the remainder of the grooves 24. The grooves 24 have vertical side walls and a bottom surface formed of the stacked structure of the first material layer 22 and the second material layer 23 in the XZ plane. Each row of the FIN structures 25 extends in the Y direction. The wall surfaces formed by the grooves 24 on both sides in the X direction of the grooves 24 are formed based on the vertical etching method (reactive ion etching), but the vertical etching method (reactive ion etching) has already been established, and the wall surfaces and bottom surface can be flat or planar. 20A(b), grooves 24 are formed to penetrate all of the repetitions of first material layers 22 and second material layers 23 deposited on substrate 21, but grooves 24 may be formed to leave some of the repetitions of first material layers 22 and second material layers 23, or in some cases, may penetrate into the surface of substrate 21. In FIG. 20A(b), the layered structure of first material layers 22 and second material layers 23 deposited on the substrate is pattern-etched, but in the present disclosure, substrate 21 may also be pattern-etched to form FIN structures 25 on the substrate surface.

[0203] 20B(c), a magnetic nanowire layer 26 is deposited over the entire surface of the FIN structure 25 created in FIG. 20B(b) by isotropic deposition. The magnetic nanowire layer 26 deposited on both wall surfaces and the bottom surface of the groove 24 is a thin film, and a slit-shaped groove 24-2 extending in the Z direction and the Y direction is formed inside the magnetic nanowire layer 26 in the groove 24. The groove 24-2 also has both vertical wall surfaces and a bottom surface in the XZ plane. The magnetic nanowire layer 26 deposited by isotropic deposition can have a uniform thickness over the entire surface. The wall surfaces formed by the groove 24 on both sides in the X direction of the groove 24 can be flat and planar, and therefore the surface of the magnetic nanowire layer 26 deposited on those wall surfaces by isotropic deposition can also be flat and planar. The isotropic deposition method for depositing a film with a uniform thickness on the wall surfaces of the vertical groove can be, for example, chemical vapor deposition (CVD) or atomic layer deposition (ALD). The magnetic nanowire layer 26 may include a spin Hall layer (not shown). It is preferable to form a protective layer (not shown) on the outermost surface of the magnetic nanowire layer 26 to prevent oxidation, but the protective layer may be formed after the step of FIG. 20(d).

[0204] The magnetic wire layer 26 includes a magnetic layer and, optionally, a spin Hall layer, and may be any of the magnetic wire layers described in the magnetic memories of the first to fourth embodiments. The first material layer 22 and the second material layer 23 can correspond to the third and fourth regions of the adjacent material layer 7 in the first to fourth embodiments. When the first material layer 22 and the second material layer 23 correspond to the third and fourth regions of the adjacent material layer 7 in the first to fourth embodiments, the magnetic layer constituting the magnetic wire layer 26 has the following characteristics: The coercivity of the magnetic material in the second region of the magnetic wire layer is greater than the coercivity of the magnetic material in the first region of the magnetic wire layer, or the product of the coercivity and the magnetic anisotropy field of the magnetic material in the second region of the magnetic wire layer is greater than the product of the coercivity and the magnetic anisotropy field of the magnetic material in the first region of the magnetic wire layer (Configuration A). Furthermore, the first material layer 22 and the second material layer 23, which are adjacent material layers adjacent to the magnetic layer, respectively, can have a third region and a fourth region of the adjacent material layer, such that the electrical conductivity of the fourth region of the adjacent material layer can be higher than that of the third region (Configuration B). When the magnetic nanowire layer 26 or the adjacent material layers (the first material layer 22 and the second material layer 23) are Configuration A or Configuration B, the threshold current density of the magnetic layer can be higher in the second region of the magnetic layer adjacent to the second material layer 23 than in the first region of the magnetic layer adjacent to the first material layer 22.

[0205] 20B(d), the FIN structure obtained after Fig. 20B(c) is pattern-etched at predetermined intervals by a vertical etching method to form slit-shaped grooves 27 extending in the X direction perpendicular to the Y direction in which the grooves 24 extend within the surface, and a structure in which magnetic memories 28 are arranged in a matrix can be formed as the remainder of the grooves 24 and 27, and the magnetic memories are insulated from each other in the Y direction by the formation of these grooves 27. Pattern etching is established, and by depositing a mask material over the entire surface and selectively removing the mask material in the areas to be etched by pattern exposure, and then etching, it is possible to selectively remove only the areas not protected by the mask and selectively leave the areas protected by the mask.

[0206] Although the explanation has been omitted above for simplicity, for example, data writing and reading means can be formed at the bottom of groove 24-2, and electrodes for applying a magnetic domain movement current can be provided to the magnetic nanowire layer 26 above the left and right sides of groove 24-2 (not shown).

[0207] Although Figures 20A and 20B show an array of magnetic memory cells arranged in a 2x2 matrix, it is clear that an array of magnetic memory cells arranged in a large number of nxn matrices can be manufactured using the above method.

[0208] Once the basic concept of this magnetic memory, i.e., three-dimensional magnetic nanowire memory, is provided, it will be clear to those skilled in the art that the methods for forming the wiring for supplying pulse current, the write section and read section, and the wiring for them in each magnetic memory can be the same as those for conventional RAMs, etc.

[0209] 21A to 21D, an example of a method for forming an adjacent material layer on a magnetic nanowire layer 26 formed on a substrate 21 will be described. An adjacent material layer consisting of a first material 22 and a second material 23 will be referred to as a first adjacent material layer 27, a second adjacent material layer on the magnetic nanowire layer 26 will be referred to as 27-2, a first material of the second adjacent material layer 27-2 will be referred to as 22-2, and a second material of the second adjacent material layer 27-2 will be referred to as 23-2. After the stage of FIG. 20B, as shown in FIG. 21A(a), a second material 23-2 of the second adjacent material layer 27-2 is deposited on the magnetic nanowire layer 26 so as to fill the groove 24-2, and then vertical etching is performed using a mask 28 that forms a groove with the same width as the groove 24-2, so that a predetermined thickness of the second material 23-2 of the second adjacent material layer 27-2 can be left at the bottom of the groove 24-2, as shown in FIG. 21A(b). At this time, the second material 23-2 of the second adjacent material layer 27-2 does not exist above the portion of the predetermined thickness remaining in the groove 24-2, and the magnetic wire layer 26 is exposed in the groove 24-2 except for the region adjacent to the remaining adjacent material layer 27-2 of the predetermined thickness. Next, as shown in Figure 21B(c), the first material 22-2 of the adjacent material layer 27-2 is deposited again on the second magnetic wire layer 26 and the second material 23-2 remaining in the groove 24-2 so as to fill the groove 24-2, and then vertical etching is performed using a mask 28, whereby the first material 22-2 of the second adjacent material layer 27-2 can be left in the groove 24-2 by a predetermined thickness as shown in Figure 21B(d). By repeating this operation, the second material 23-2 and the first material 22-2 of the second adjacent material layer 27-2 can be repeatedly deposited to a predetermined thickness within the groove 24-2, as shown in Figure 21C(e). After the second material 23-2 and the first material 22-2 of the second adjacent material layer 27-2 are repeatedly deposited to a predetermined thickness within the groove 24-2, vertical etching is performed using a mask 28-2 to form a groove 24-4 narrower than the groove 24-2, as shown in Figure 21C(f). As a result, the adjacent material layer 27-2 can remain on the left and right walls and bottom of the original groove 24-2, each with a predetermined thickness, as shown in Figure 21C(g).Although not described above for simplicity, before or after depositing the second adjacent material layer 27-2 in the groove 24-2, any adjacent material layer continuous with the second adjacent material layer 27-2 of a special shape and dimensions at the bottom of the groove 24-2 can be deposited, and data writing and reading means can be formed in the groove 24-2 (not shown). Also, before or after depositing the second adjacent material layer 27-2 in the groove 24-2, electrodes for applying a magnetic domain movement current to the magnetic nanowire layer 26 located above the left and right sides of the groove 24-2 (24-4) can be provided (not shown). Here, for example, the second material 23-2 of the second adjacent material layer 26-2 and the first material 22-2 can have a higher electrical conductivity than the first material 22-2 so as to satisfy the requirements of the second aspect (form B) of the present disclosure. At this time, the second adjacent material layer 27-2 formed in the groove 24-2 is the adjacent material layer of the second aspect (form B) of the present disclosure.

[0210] In the present disclosure, when the second adjacent material layer 27-2 formed in the groove 24-2 is included as the adjacent material layer on the second side surface, the first adjacent material layer 27 consisting of the first material 22 and the second material 23 formed in Figures 20A(a) and 20A(b) can be the adjacent material layer on the first side surface (form A), and the second adjacent material layer 27-2 can be the adjacent material layer on the second side surface (form B). Alternatively, with the second adjacent material layer 27-2 as the adjacent material layer on the second side surface (form B), the portion corresponding to the first adjacent material layer 27 can be formed entirely of the second material 23 in a single step, without distinguishing between the first material 22 and the second material 23. The second material 23 is a material that can induce high magnetic anisotropy (coercive force, magnetic anisotropy field) in the magnetic nanowire layer 26, and is therefore a preferred substrate for the magnetic nanowire layer 26.

[0211] As described in the explanation of the first embodiment, a two-dimensional magnetic memory based on the present disclosure can be manufactured by patterning a first material formed on a substrate and selectively filling the grooves formed between the patterns of the first material with a second material, thereby creating an adjacent material layer including the first material (third region) and the second material (fourth region), and then depositing a magnetic layer or the like on the adjacent material layer.

[0212] According to the magnetic memory manufacturing method of the present disclosure, a FIN structure is used as a method for linearly forming and isolating a magnetic nanowire layer deposited in a vertical groove in a three-dimensional magnetic nanowire memory. Furthermore, particularly in the case of the magnetic memory provided based on the present disclosure in which the threshold current density of the magnetic nanowire layer is locally changed by an adjacent material, the magnetic nanowire layer deposited in the vertical groove can be deposited and formed in a vertical groove whose width dimension does not change in the vertical direction and which may be flat in a preferred embodiment. Therefore, compared to the conventional technology using a vertical groove whose width dimension changes in the vertical direction, the manufacturing process is established and simple.

[0213] <Memory Cell Assembly> According to the present disclosure, in a second aspect, there is provided a magnetic memory assembly comprising a plurality of the above-described magnetic memories and a control unit that controls the plurality of magnetic memories, wherein the magnetic memories comprise a write unit, a read unit, first and second wirings as a pair of wirings for supplying the pulse current, a third wiring connected to the write unit, and a fourth wiring connected to the read unit.

[0214] Structures for arranging memory cells in a grid pattern to form memory cell arrays and memory cell assemblies are well known in the field of NAND and the like. Therefore, a memory cell assembly can be similarly constructed using the cells of the magnetic memory of the present disclosure. Therefore, detailed descriptions of the structures of memory cell arrays and memory cell assemblies using memory cells are unnecessary and can be omitted.

[0215] FIG. 21 schematically shows an example of a magnetic memory assembly 30. In FIG. 21, magnetic memory cells 1 are arranged in a lattice pattern. Each memory cell 1 has a pair of shift electrodes S1 and S2, a pair of write electrodes W1 and W2, and a read electrode R. Of the pair of shift electrodes S1 and S2, one shift electrode S1 is connected to a vertical wiring SL1, and the other shift electrode S2 is connected to a horizontal wiring SL2. By selecting specific wiring SL1 and specific wiring SL2 and passing a current through them, the domain wall (magnetic domain) in a specific memory cell can be shifted. By reversing the direction of the current, the shift can be made in the opposite direction.

[0216] A pair of write electrodes W1, W2 has one write electrode W1 connected to a vertical wiring WL1 and the other write electrode W2 connected to a horizontal wiring WL2, and by selecting a specific wiring WL1 and a specific wiring WL2 and passing a current between them, data can be written in the write section of a specific memory cell.

[0217] The read electrode R is connected to a vertical wiring RL, and the opposite electrode of the read section may be, for example, a write electrode W2. Therefore, by selecting a specific wiring RL and a specific wiring WL2 and applying a voltage between them, data can be read in the read section of a specific memory cell.

[0218] Fig. 22 shows only a portion of a memory cell array, and it is possible to have a larger number of memory cells both vertically and horizontally, and it is possible to configure a memory cell array having an even larger number of memory cells by stacking planar memory cell arrays such as those shown in Fig. 22 in the vertical direction. Note that Fig. 22 is merely one example of a memory cell array, and various modifications are possible.

[0219] The memory cell assembly of the present disclosure includes a memory cell array that stores the above-mentioned data, as well as a horizontal line control circuit that controls multiple horizontal lines of the memory cell array, a vertical line control circuit that controls multiple vertical lines of the memory cell array, a write circuit that performs various controls for write operations, a read circuit that performs various controls for read operations, a shift circuit that performs various controls for shifting data, an input / output circuit that is an interface circuit for transferring various signals, a voltage generation circuit that generates voltages for various operations of the memory cell array using power supply voltage provided from a power supply, and a control circuit that controls the operation of each circuit in the memory device based on a control signal T, an address, and a command.

[0220] The magnetic memory based on this disclosure is a so-called magnetic nanowire memory, and can be used as "large-capacity," "high-speed," and "non-volatile" storage for mobile devices and data centers. Magnetic nanowire memory is expected to be the next generation of storage after three-dimensional (3D-) NAND flash, which vertically stacks NAND flash memories that store electric charge in the gate insulating film of field-effect transistors to record data, and the magnetic memory based on this disclosure will contribute to its practical application.

[0221] 1 Magnetic memory (first embodiment) 1-2 Magnetic memory (second embodiment) 2 Substrate 3 Groove 4 Magnetic layer 5 Spin Hall layer 6 Magnetic nanowire layer 7 Adjacent material layer 7a Third region (first material) 7b Fourth region (second material) 8 Wiring 9 Write member 10 Read member 11 Domain wall 21 Substrate 22 Layer of first material 23 Layer of second material 24 Groove (ZY direction) 24-2 Groove (ZY direction) 25 FIN structure 26 Magnetic nanowire layer 27 Groove (ZX direction)

Claims

1. 1. A magnetic memory having a first direction and a second direction intersecting the first direction, substrate; a magnetic nanowire layer including a magnetic layer or a magnetic layer and a spin Hall layer, and including a first region and a second region in the first direction as a data storage region; an adjacent material layer that is adjacent to the magnetic nanowire layer in the second direction and is made of a nonmagnetic material that does not have intrinsic magnetization, the adjacent material layer including a third region and a fourth region in the first direction, the third region being in the second direction of the first region, and the fourth region being in the second direction of the second region; and a circuit that applies a pulse current to the magnetic nanowire layer to move a domain wall in the magnetic layer in a direction from the first region toward the second region; Equipped with The first material constituting the third region and the second material constituting the fourth region of the adjacent material layer are different materials from each other and satisfy the following requirements A and B: A) The first material and the second material of the adjacent material layer are materials that can induce magnetic anisotropy in the magnetic layer of the first region and the second region of the magnetic wire layer, and the intrinsic coercivity of the magnetic layer of the second region of the magnetic wire layer is greater than the intrinsic coercivity of the magnetic layer of the first region of the magnetic wire layer, or the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer of the second region of the magnetic wire layer is greater than the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer of the first region of the magnetic wire layer (Feature A); and B) the electrical conductivity of the fourth region of the adjacent material layer is higher than the electrical conductivity of the third region (form B); At least one of the following is satisfied: the first region of the magnetic wire layer has a first threshold current density, and the second region of the magnetic wire layer has a second threshold current density, wherein the first threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer required to move a domain wall in the magnetic layer in the first region, and the second threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer required to move a domain wall in the magnetic layer in the second region, and the second threshold current density is greater than the first threshold current density; A magnetic memory characterized by:

2. In the case of form A, the difference in the intrinsic coercivity or the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer between the first region and the second region of the magnetic layer is due to the difference in the crystal structure or crystal orientation of the magnetic layer between the first region and the second region, the difference in the crystal structure or crystal orientation of the magnetic layer between the first region and the second region is due to the influence of the material of the third region and the material of the fourth region of the adjacent material layer, and the difference between the first threshold current density and the second threshold current density of the magnetic layer is the difference in the threshold current density of the magnetic wire layer itself observed in a current flowing through the magnetic wire layer in its length direction under a condition where there is no influence of a magnetic field or electric field in the cross-sectional direction of the magnetic wire layer, In the case of the form B, the difference between the first threshold current density and the second threshold current density of the magnetic wire layer is a result of causing a difference between a ratio of the current flowing through the first region of the magnetic wire layer and the current branching into the third region of the adjacent material layer and a ratio of the current flowing through the second region of the magnetic wire layer and the current branching into the fourth region of the adjacent material layer, based on a difference between the electrical conductivity of the third region and the electrical conductivity of the fourth region of the adjacent material layer, resulting in a difference in the amount of current flowing through the magnetic layer in the second region of the magnetic wire layer and the magnetic layer in the first region.

2. The magnetic memory according to claim 1.

3. 2. The magnetic memory of claim 1, wherein in the case of form A, the coercivity or the product of the coercivity and the magnetic anisotropy field of the magnetic layer in the second region is 1.5 times or more larger than the coercivity or the product of the coercivity and the magnetic anisotropy field of the magnetic layer in the first region; and in the case of form B, when the magnetic wire layer includes the magnetic layer but not the spin Hall layer, the amount of current flowing through the second region of the magnetic wire layer is reduced by at least 20% compared to the amount of current flowing through the first region; and when the magnetic wire layer includes the magnetic layer and the spin Hall layer, the amount of current flowing through the spin Hall layer in the second region of the magnetic wire layer is reduced by at least 5% compared to the amount of current flowing through the spin Hall layer in the first region.

4. 2. The magnetic memory of claim 1, wherein in form A, the adjacent material layer is formed on the substrate side of the magnetic nanowire layer, and in form B, the adjacent material layer is formed on at least one of the substrate side and the side opposite the substrate of the magnetic nanowire layer.

5. 2. The magnetic memory of claim 1, wherein the fourth region of the adjacent layer of material is made of CrOx, and the third region of the adjacent layer of material is made of a material selected from GdOx, NiOx, and MgO.

6. 2. The magnetic memory of claim 1, wherein the third region of the adjacent material layer is a non-magnetic material having no intrinsic magnetization and an insulating material, and the fourth region of the adjacent material layer is a non-magnetic material having no intrinsic magnetization and a metal or a conductive semiconductor.

7. 2. The magnetic memory of claim 1, wherein the magnetic wire layer includes a spin Hall layer adjacent to the magnetic layer on the side of the adjacent material layer or on the side of the magnetic layer opposite the adjacent material layer.

8. a substrate having a surface including a third direction and a fourth direction intersecting with each other, a direction perpendicular to the surface being a fifth direction, and the surface side of the substrate being above the fifth direction; the adjacent layer of material on the substrate; a first groove extending in the fifth direction from the adjacent material layer side toward the bottom surface of the substrate and in the fourth direction; the first groove has a first wall surface on one side in the third direction, a second wall surface on the other side in the third direction, and a bottom surface; the adjacent material layer is present on at least both the first wall surface side and the second wall surface side of the first groove, the adjacent material layer includes a first portion having the first wall surface and a second portion having the second wall surface, and the adjacent material layer includes the third region and the fourth region aligned in the fifth direction in both the first portion and the second portion, the magnetic nanowire layer exists continuously from above the first wall surface, through above the bottom surface of the first groove, to above the second wall surface, and a second groove exists between the magnetic nanowire layer on the first wall surface and the magnetic nanowire layer on the second wall surface, the second groove extending in both the fourth direction and the fifth direction; the magnetic nanowire layer includes a fifth region extending above the first portion of the adjacent material layer in the fifth direction, a sixth region extending above the second portion of the adjacent material layer in the fifth direction, and a seventh region on the bottom surface of the first groove; a write section is provided in the seventh region of the magnetic nanowire layer, a readout section is provided in the seventh region of the magnetic nanowire layer; a pair of wirings for applying a pulse current between the fifth region and the sixth region of the magnetic nanowire layer; 2. The magnetic memory according to claim 1.

9. A magnetic memory assembly comprising a plurality of magnetic memories according to any one of claims 1 to 8 and a control unit for controlling the plurality of magnetic memories, wherein the magnetic memories comprise a writing unit, a reading unit, first and second wiring for applying the pulse current, a third wiring connected to the writing unit, and a fourth wiring connected to the reading unit.

10. A method for manufacturing a magnetic memory, the magnetic memory having a first direction and a second direction intersecting the first direction, the method comprising: providing an adjacent material layer made of a nonmagnetic material on a substrate, the adjacent material layer including a third region and a fourth region in the first direction, wherein a first material constituting the third region and a second material constituting the fourth region of the adjacent material layer are different materials from each other; a magnetic wire layer including a magnetic layer or a magnetic layer and a spin Hall layer is formed on the substrate, the magnetic wire layer including a first region and a second region adjacent to the adjacent material layer in the second direction and in the first direction as a data storage region, the first region being present in the second direction of the third region, and the second region being present in the second direction of the fourth region; wherein the adjacent material layers are the following A and B: A) The first material and the second material of the adjacent material layer are materials that can induce magnetic anisotropy in the first region and the second region of the magnetic wire layer, and the first material and the second material of the adjacent material layer are selected so that the intrinsic coercivity of the magnetic layer in the second region of the magnetic wire layer is greater than the intrinsic coercivity of the magnetic layer in the first region of the magnetic wire layer, or the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer in the second region of the magnetic wire layer is greater than the product of the intrinsic coercivity and the intrinsic magnetic anisotropy field of the magnetic layer in the first region of the magnetic wire layer (Feature A); and B) the electrical conductivity of the fourth region of the adjacent material layer is selected to be higher than the electrical conductivity of the third region (form B); At least one of the following requirements must be met: a circuit for applying a pulse current to the magnetic nanowire layer to move a domain wall in the magnetic layer; the first region of the magnetic wire layer formed adjacent to the adjacent material layer has a first threshold current density, and the second region of the magnetic wire layer has a second threshold current density, wherein the first threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer necessary to move a domain wall in the magnetic layer in the first region, and the second threshold current density refers to the minimum current density of the pulse current to be applied to the magnetic wire layer necessary to move a domain wall in the magnetic layer in the second region, and the second threshold current density is greater than the first threshold current density; A method for manufacturing a magnetic memory, comprising:

11. the magnetic memory comprises the magnetic nanowire layer, the adjacent material layer, and the circuit on a substrate, the surface of the substrate includes an eleventh direction and a twelfth direction intersecting with each other, and a direction intersecting with the surface of the substrate is a thirteenth direction; depositing a first zone of the first material and a second zone of the second material in the thirteenth direction as the adjacent material layers on the substrate; forming a first groove in the adjacent material layer on the substrate, the first groove extending in the thirteenth direction and the twelfth direction from the adjacent material layer toward the substrate, the first groove being formed to penetrate the first band and the second band, so that in a vertical cross section including the eleventh direction and the thirteenth direction, the first groove has a first wall surface on one side of the first groove in the eleventh direction, a second wall surface on the other side, and a bottom surface, and a first portion of the adjacent material layer having the first wall surface on the one side of the first groove, and a second portion of the adjacent material layer having the second wall surface on the other side of the first groove; depositing the magnetic wire layer continuously extending from above the first portion of the adjacent material layer in the thirteenth direction, via the first wall surface of the adjacent material layer, the bottom surface of the first groove, and the second wall surface of the adjacent material layer, to above the second portion of the adjacent material layer in the thirteenth direction, and the deposited magnetic wire layer has a second groove extending in the thirteenth direction and a twelfth direction between the magnetic wire layer on the first wall surface and the magnetic wire layer on the second wall surface; when the substrate is viewed from the thirteenth direction, the magnetic wire layer has a third portion extending in the eleventh direction, and fourth and fifth portions located on both sides of the third portion in the twelfth direction and extending in the eleventh direction, and the third portion of the magnetic wire layer is isolated by selectively removing the fourth and fifth portions of the magnetic wire layer; Including, and the first zone of the first material is the third region of the adjacent material, and the second zone of the second material is the fourth region of the adjacent material.

11. The method for manufacturing a magnetic memory according to claim 10.

12. 12. The method for manufacturing a magnetic memory according to claim 10, wherein the deposition of the magnetic nanowire layer includes depositing the magnetic layer and depositing a spin Hall layer adjacent to the magnetic layer on at least one of the side of the adjacent material layer or the side of the magnetic layer opposite to the adjacent material layer.

13. 12. A method for manufacturing a magnetic memory as described in claim 10 or 11, wherein the first groove is formed by anisotropic etching in the thirteenth direction, and the first wall surface and the second wall surface of the first groove and the surface of the deposited magnetic nanowire layer on the second groove side are straight lines in a vertical cross section including an axis in the thirteenth direction.

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