Magnetic domain wall moving element and magnetic array

Abstract

The invention discloses a magnetic domain wall moving element. The domain wall moving element includes a first ferromagnetic layer, a first magnetization fixing portion, and a second magnetization fixing portion. The first magnetization fixing part comprises a first magnetization fixing layer, a first non-magnetic layer and a second magnetization fixing layer, and the second magnetization fixing layer is provided with a first anti-diffusion structure. The second fixed magnetization portion includes a third fixed magnetization layer, a second non-magnetic layer, and a fourth fixed magnetization layer. The fourth magnetization fixed layer has a second anti-diffusion structure and a first region. The first region is located further away from the second non-magnetic layer than the second diffusion prevention structure. The first region contains a ferromagnetic element and a non-magnetic element.

Description

Technical Field

[0001] The present disclosure relates to a magnetic domain wall motion element and a magnetic array. Background Art

[0002] There are known magnetoresistive elements that change the resistance value (magnetoresistance change) by using the relative angle change of magnetization between two ferromagnetic layers. For example, a magnetic domain wall motion type magnetoresistive element (hereinafter referred to as a magnetic domain wall motion element) described in Patent Document 1 is an example of a magnetoresistive element. In the magnetic domain wall motion element, the resistance value in the stacking direction changes according to the position of the domain wall, and data can be recorded in a multi-level or analog manner. The magnetic domain wall motion element has high linearity and symmetry of resistance change and excellent rewrite resistance, and can operate at high speed.

[0003] Patent Document 1 describes magnetization fixing portions that limit the movement range of the domain wall at both ends of the magnetic recording layer. The magnetization orientation directions of the two magnetization fixing portions are different from each other.

[0004] [Patent Document]

[0005] [Patent Document 1] PCT International Publication with Publication Number WO2020 / 230877 Summary of the Invention

[0006] It is not easy to direct the magnetization orientation directions of the two magnetization fixing portions in different directions.

[0007] The present disclosure is implemented in view of the above problems, and an object of the present disclosure is to provide a magnetic domain wall motion element and a magnetic array with high reliability.

[0008] The magnetic domain wall motion element according to the first aspect includes: a first ferromagnetic layer having domain walls inside; a first magnetization fixing portion connected to the first ferromagnetic layer; and a second magnetization fixing portion connected to the first ferromagnetic layer at a position separated from the first magnetization fixing portion. The first magnetization fixing portion includes a first magnetization fixing layer, a first nonmagnetic layer, and a second magnetization fixing layer. The first magnetization fixing layer and the second magnetization fixing layer are antiferromagnetically coupled to each other, and the first nonmagnetic layer is interposed between the first magnetization fixing layer and the second magnetization fixing layer. The first magnetization fixing layer is in contact with the first ferromagnetic layer. The first nonmagnetic layer is located between the first magnetization fixing layer and the second magnetization fixing layer in the stacking direction. The second magnetization fixing layer has a first anti-diffusion structure. The second magnetization fixing portion includes a third magnetization fixing layer, a second nonmagnetic layer, and a fourth magnetization fixing layer. The third magnetization fixing layer and the fourth magnetization fixing layer are antiferromagnetically coupled to each other, and the second nonmagnetic layer is interposed between the third magnetization fixing layer and the fourth magnetization fixing layer. The third magnetization fixing layer is in contact with the first ferromagnetic layer. The second nonmagnetic layer is located between the third magnetization fixing layer and the fourth magnetization fixing layer in the stacking direction. The fourth magnetization fixing layer has a second anti-diffusion structure and a first region. The first region is located at a position further away from the second nonmagnetic layer than the second anti-diffusion structure. The first region contains a ferromagnetic element and a nonmagnetic element. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 is a block diagram of a magnetic array according to the first embodiment.

[0010] Figure 2 is a circuit diagram of an integrated region of a magnetic array according to the first embodiment.

[0011] Figure 3 is a cross-sectional view near a magnetic domain wall motion element of a magnetic array according to the first embodiment.

[0012] Figure 4 is a cross-sectional view of a magnetic domain wall motion element according to the first embodiment.

[0013] Figure 5 is a plan view of a magnetic domain wall motion element according to the first embodiment.

[0014] Figure 6 is a cross-sectional view of the first magnetization fixing portion according to the first embodiment.

[0015] Figure 7 is a cross-sectional view of the second magnetization fixing portion according to the first embodiment.

[0016] Figure 8 is a conceptual diagram of a neural network.

[0017] Figure 9 is a block diagram showing a system including a neuromorphic device according to the first embodiment. DETAILED DESCRIPTION

[0018] Hereinafter, this embodiment will be described in detail with reference to appropriate drawings. In the drawings used in the following description, in order to facilitate understanding of the features of this embodiment, the feature portions may be enlarged, and the dimensional ratios of each component may be different from the actual ones. The materials, dimensions, etc. exemplified in the following description are examples, and this embodiment is not limited thereto, and may be appropriately modified and implemented within the range of showing the effects of this embodiment.

[0019] First, the directions will be defined. The x-direction and the y-direction are directions substantially parallel to one surface of the substrate Sub (see Figure 3 ). The x-direction is the direction in which the first ferromagnetic layer to be described below extends. The y-direction is a direction orthogonal to the x-direction. The z-direction is the direction from the substrate toward the domain wall moving element, and the domain wall moving element will be described below. The z-direction is an example of the stacking direction. In this specification, the +z direction may be expressed as "upward", and the -z direction may be expressed as "downward", but these expressions are for convenience and do not define the direction of gravity. Further, in this specification, the term "extending in the x-direction" means that, for example, the dimension in the x-direction is greater than the minimum dimension among the dimensions in the x-direction, y-direction, and z-direction. The same applies to the case of extending in other directions.

[0020] [First Embodiment]

[0021] Figure 1 is a block diagram of the magnetic array MA according to the first embodiment. The magnetic array MA has an integration region 1 and a peripheral region 2. The magnetic array MA can be used for, for example, a magnetic memory, a multiply-accumulate computing device, a neuromorphic device, a spin memristor, or a magneto-optical element.

[0022] The integration region 1 is a region where a plurality of domain wall moving elements are integrated. When the magnetic array MA is used as a memory, data is accumulated in the integration region 1. When the magnetic array MA is used as a neuromorphic device, learning and inference are performed in the integration region 1.

[0023] The peripheral region 2 is a region where control elements are installed, and the control elements control the operations of the domain wall moving elements in the integration region 1. The peripheral region 2 includes, for example, a control device 3, a resistance detection device 4, and an output component 5.

[0024] The control device 3 is configured to be able to apply a pulse to at least one of the plurality of domain wall moving elements in the integration region 1. The control device 3 includes, for example, a control component 6 and a power supply 7.

[0025] The control unit 6 includes, for example, a processor and a memory. The processor is, for example, a central processing unit (CPU). The processor operates based on an operation program stored in the memory. The control unit 6 controls, for example, the address of the magnetic domain wall movement element to which a pulse is applied, the amplitude (voltage, pulse length) of the pulse applied to a predetermined magnetic domain wall movement element, and the like. In addition to this, the control unit 6 may also include a clock, a counter, a random number generator, and the like. The clock serves as an indicator of the time when a pulse is applied, and the counter counts the number of times a pulse is applied. The power supply 7 applies a pulse to the magnetic domain wall movement element according to an instruction from the control unit 6.

[0026] The resistance detection device 4 is configured to be able to detect the resistance value of the magnetic domain wall movement element within the integration region 1. For example, the resistance detection device 4 may detect the resistance of each magnetic domain wall movement element within the integration region 1, or may detect the total resistance of the magnetic domain wall movement elements belonging to the same column. For example, the resistance detection device 4 may detect the current value flowing through a reference resistor, or may once store the output as a charge in a capacitor and then detect the charge. The resistance detection device 4 may have, for example, a comparator that is used to perform a comparison of the magnitudes of the detected resistance values. The comparator may, for example, compare the detected resistance values with each other, or compare the detected resistance values with a preset reference resistance value.

[0027] The output component 5 is connected to the resistance detection device 4. The output component 5 includes, for example, a processor, an output capacitor, an amplifier, a converter, and the like. In the case where the magnetic array MA is used as a neuromorphic device, the output component 5 may perform a calculation of substituting the detection result of the resistance detection device 4 into an activation function. This calculation is performed by the processor, for example. The output component 5 outputs the calculation result to the outside. In the case where the magnetic array MA is used as a neuromorphic device, for example, an operation such as outputting the calculation result as an input signal to another magnetic array may be performed, or an operation such as outputting the calculation result as a recognition rate to the outside may be performed. Further, the output component 5 may feedback the calculation result to the control device 3.

[0028] Figure 2 is a circuit diagram of the integration region 1 according to the first embodiment. The integration region 1 includes a plurality of magnetic domain wall movement elements 100, a plurality of write wirings WL, a plurality of common wirings CL, a plurality of read wirings RL, a plurality of first switches SW1, and a plurality of second switches SW2. The third switch SW3 may belong to the control device 3 of the peripheral region 2, for example.

[0029] The plurality of magnetic domain wall movement elements 100 are arranged in a matrix form, for example. The plurality of magnetic domain wall movement elements 100 are not limited to the actual elements being arranged in a matrix form, and for example, the actual elements may be arranged in a three-dimensional form and arranged in a matrix form in the circuit diagram.

[0030] Each of the write wirings WL is used when writing data. Each of the write wirings WL electrically connects the control device 3 to one or more magnetic domain wall movement elements 100 to each other. Each of the common wirings CL is used both when writing data and when reading data. Each of the common wirings CL is connected to, for example, the resistance detection device 4. Each of the common wirings CL may be provided in one of the plurality of magnetic domain wall movement elements 100, or may be provided above the plurality of magnetic domain wall movement elements 100. Each of the read wirings RL is used when reading data. Each of the read wirings RL electrically connects the control device 3 to one or more magnetic domain wall movement elements 100 to each other.

[0031] Each of the first switch SW1, the second switch SW2, and the third switch SW3 is an element that controls the flow of current. Each of the first switch SW1, the second switch SW2, and the third switch SW3 is, for example, a transistor, an element such as an ovonic threshold switch (OTS) that utilizes the phase change of a crystal layer, an element such as a metal insulator transition (MIT) switch that utilizes the change in the energy band structure, an element such as a Zener diode or an avalanche diode that utilizes the breakdown voltage, or an element whose conductivity changes as the atomic position changes.

[0032] For example, the first switch SW1 and the second switch SW2 are connected to each magnetic domain wall movement element 100 one by one. For example, the first switch SW1 is connected between the magnetic domain wall movement element 100 and the write wiring WL. For example, the second switch SW2 is connected between the magnetic domain wall movement element 100 and the common wiring CL. For example, the third switch SW3 is provided above the plurality of magnetic domain wall movement elements 100. For example, the third switch SW3 is connected to the read wiring RL.

[0033] The positional relationship among the first switch SW1, the second switch SW2, and the third switch SW3 is not limited to Figure 2 the case shown. For example, the first switch SW1 may be connected above the plurality of magnetic domain wall movement elements 100 and may be located upstream of the write wiring WL. Further, for example, the second switch SW2 may be connected above the plurality of magnetic domain wall movement elements 100 and may be located upstream of the common wiring CL. Further, for example, the third switch SW3 may be connected to each magnetic domain wall movement element 100 one by one.

[0034] Figure 3 is a cross-sectional view near the magnetic domain wall movement element 100 of the integrated region 1 according to the first embodiment. Figure 3 is Figure 2 a cross-section of one of the magnetic domain wall movement elements 100 along the xz plane, where the xz plane passes through the width center of the first ferromagnetic layer 10 in the y direction.

[0035] Figure 3Each of the first switch SW1 and the second switch SW2 shown is a transistor Tr. The transistor Tr has a gate electrode G, a gate insulating film GI, a source S, and a drain D. The source S and the drain D are predetermined according to the direction of current flow and are both active regions of a semiconductor. Figure 3 Only one example is shown, and the positional relationship between the source S and the drain D may be interchanged. The substrate Sub is, for example, a semiconductor substrate. The third switch SW3 is electrically connected to the read wiring RL and is, for example, located along the Figure 3 The y-direction offset position.

[0036] The transistor Tr, write wiring WL, common wiring CL, read wiring RL, and magnetic domain wall moving element 100 are connected via via wiring V extending in the z-direction or in-plane wiring IP extending in any direction within the xy plane. The via wiring V and in-plane wiring IP contain a conductive material. In addition to the via wiring V, an insulating layer 90 is formed between different layers in the z-direction.

[0037] The insulating layer 90 is an insulating layer that insulates a portion between the wirings arranged in multiple layers and a portion between the elements. The magnetic domain wall moving element 100 and the transistor Tr are electrically isolated by the insulating layer 90 except for the via wiring V. The insulating layer 90 is made of, for example, silicon oxide (SiO x ), silicon nitride (SiN x ), silicon carbide (SiC), chromium nitride, silicon carbonitride (SiCN), silicon oxynitride (SiON), aluminum oxide (Al2O3), zirconium oxide (ZrO x ) and so on.

[0038] Figure 4 1 is a cross-sectional view of the magnetic domain wall moving element 100 along the xz plane passing through the center in the y direction of the first ferromagnetic layer 10. The arrows shown in the figure are examples of magnetization orientation directions of the ferromagnetic material in an initial state in which no external magnetic field is applied to the magnetic domain wall moving element 100. Figure 5 is a plan view of the magnetic domain wall moving element 100 in the z direction.

[0039] The magnetic domain wall moving element 100 includes, for example, a first ferromagnetic layer 10, a non-magnetic layer 20, a second ferromagnetic layer 30, a first magnetization fixing portion 40, a second magnetization fixing portion 50, a first electrode E1, a second electrode E2, and a third electrode E3. Each of the plurality of magnetic domain wall moving elements included in the integrated region 1 is Figure 4 and Figure 5 The magnetic domain wall moving element 100 is shown.

[0040] The first ferromagnetic layer 10 extends in the x direction. When viewed from the z direction, the length of the first ferromagnetic layer 10 in the x direction is greater than the length in the y direction. The first ferromagnetic layer 10 has two domains inside, and a domain wall DW is present at the boundary between the two domains. The first ferromagnetic layer 10 is a layer that can, for example, magnetically record information by changing its magnetic state. The first ferromagnetic layer 10 is also referred to as an analog layer, a magnetic recording layer, or a magnetic domain wall motion layer.

[0041] The first ferromagnetic layer 10 has a first magnetization region A1, a second magnetization region A2, and a third magnetization region A3.

[0042] The first magnetization region A1 is a region where the orientation direction of the magnetization M A1 is fixed in one direction. In the state where the magnetization is fixed, during the normal operation of the magnetic domain wall motion element 100 (without applying an external force exceeding a hypothetical value), the magnetization does not reverse. The first magnetization region A1 is, for example, the region of the first ferromagnetic layer 10 that overlaps with the first magnetization fixing portion 40 when viewed from the z direction. The magnetization M of the first magnetization region A1 A1 is fixed, for example, by the magnetization M of the first magnetization fixing layer 41 of the first magnetization fixing portion 40. 41

[0043] The second magnetization region A2 is a region where the orientation direction of the magnetization M A2 is fixed in one direction. The orientation direction of the magnetization M of the second magnetization region A2 A2 is different from the orientation direction of the magnetization M of the first magnetization region A1. A1 The orientation direction of the magnetization M of the second magnetization region A2 A2 is, for example, opposite to the orientation direction of the magnetization M of the first magnetization region A1. A1 The second magnetization region A2 is, for example, the region of the first ferromagnetic layer 10 that overlaps with the second magnetization fixing portion 50 when viewed from the z direction. The magnetization M of the second magnetization region A2 A2 is fixed, for example, by the magnetization M of the third magnetization fixing layer 51 of the second magnetization fixing portion 50. 51 For example, the magnetization arrangement shown in Figure 4 can be achieved by first applying an extremely strong magnetic field in the upward direction to align all the ferromagnetic layers in the same direction, and then removing the magnetic field to return to the zero - magnetic - field state. This operation is, for example, called an initialization process.

[0044] The third magnetization region A3 is the region of the first ferromagnetic layer 10 other than the first magnetization region A1 and the second magnetization region A2. The third magnetization region A3 is, for example, the region between the first magnetization region A1 and the second magnetization region A2 in the x direction.

[0045] The third magnetization region A3 is a region where the magnetization direction can be changed and the domain wall DW can move. The third magnetization region A3 is referred to as a domain-wall movable region. The third magnetization region A3 has a first domain A31 and a second domain A32. The first domain A31 and the second domain A32 have opposite magnetization orientation directions. The boundary between the first domain A31 and the second domain A32 is the domain wall DW. The magnetization M of the first domain A31 A31 for example, is in the same direction as the magnetization M of the first magnetization region A1 A1 The magnetization M of the second domain A32 A32 for example, is in the same direction as the magnetization M of the adjacent second magnetization region A2 A2 In principle, the domain wall DW moves in the third magnetization region A3 without invading the first magnetization region A1 and the second magnetization region A2.

[0046] When the volume ratio of the first domain A31 and the second domain A32 in the third magnetization region A3 changes, the domain wall DW moves. By allowing a write current to flow in the x direction of the third magnetization region A3, the domain wall DW is moved. For example, when a write current (e.g., a current pulse) is applied in the +x direction of the third magnetization region A3, electrons flow in the -x direction opposite to the current, and thus the domain wall DW moves in the -x direction. In the case where the current flows from the first domain A31 to the second domain A32, the electrons spin-polarized in the second domain A32 cause the magnetization M of the first domain A31 A31 to be reversed. By reversing the magnetization M of the first domain A31 A31 , the domain wall DW is moved in the +x direction.

[0047] The first ferromagnetic layer 10 is made of a magnetic material. The first ferromagnetic layer 10 can be a ferromagnetic material, a ferrimagnetic material, or a combination of these materials and an antiferromagnetic material whose magnetic state can be changed by an electric current. Preferably, the first ferromagnetic layer 10 has at least one element selected from the group consisting of Co, Ni, Fe, Pt, Pd, Gd, Tb, Mn, Ge, and Ga.

[0048] Examples of the materials used for the first ferromagnetic layer 10 include a stacked film of Co and Ni, a stacked film of Co and Pt, a stacked film of Co and Pd, Co x Fe 1-xStacked films of B (0 ≤ x ≤ 1) and the same materials as the non-magnetic layer 20 described below, MnGa-based materials, GdCo-based materials, and TbCo-based materials. Among ferromagnetic materials such as MnGa-based materials, GdCo-based materials, and TbCo-based materials, the saturation magnetization is small, and the threshold current required to move the domain wall DW is small. Further, in stacked films of Co and Ni, Co and Pt, Co and Pd, the coercive force is large, and the movement speed of the domain wall DW is slow. Antiferromagnetic materials are, for example, Mn3X (X is Sn, Ge, Ga, Pt, Ir, etc.), CuMnAs, Mn2Au, etc. The first ferromagnetic layer 10 can also be made of the same material as the second ferromagnetic layer 30 described below. The first ferromagnetic layer 10 can also be made of two or more stacked films and materials.

[0049] The non-magnetic layer 20 is interposed between the first ferromagnetic layer 10 and the second ferromagnetic layer 30 in the z direction. The non-magnetic layer 20 is an example of the third non-magnetic layer. The non-magnetic layer 20 suppresses the magnetic coupling between the first ferromagnetic layer 10 and the second ferromagnetic layer 30. The non-magnetic layer 20 is stacked on one surface of the second ferromagnetic layer 30.

[0050] The non-magnetic layer 20 is made of, for example, a non-magnetic insulator, semiconductor, or metal. Preferably, the non-magnetic layer 20 is made of a non-magnetic insulator, for example. Non-magnetic insulators are, for example, Al2O3, SiO2, MgO, MgAl2O4, or materials in which some of Al, Si, or Mg in Al2O3, SiO2, MgO, or MgAl2O4 are replaced by Zn, Be, Ga, Ti, etc. These materials have a large band gap and excellent insulating properties. Non-magnetic insulators are, for example, oxides containing Mg or Al. When the non-magnetic layer 20 is made of a non-magnetic insulator, the non-magnetic layer 20 is a tunneling barrier layer. Non-magnetic metals are, for example, Cu, Au, Ag, etc. Non-magnetic semiconductors are, for example, Si, Ge, CuInSe2, CuGaSe2, Cu(In, Ga)Se2, etc.

[0051] The thickness of the non-magnetic layer 20 is, for example, 20 Å or more, and can be 25 Å or more. The thickness of each layer is the average value of the height of the layer measured at 5 different points in the x direction in the z direction.

[0052] The non-magnetic layer 20 is interposed between the second ferromagnetic layer 30 and the first ferromagnetic layer 10. The second ferromagnetic layer 30 is located at a position where at least a part of it overlaps with the third magnetization region A3 in the z direction. For example, the second ferromagnetic layer 30 is closer to the substrate Sub than the first ferromagnetic layer 10.

[0053] The magnetization M of the second ferromagnetic layer 30 30 is more difficult to reverse than the magnetization of the third magnetization region A3 of the first ferromagnetic layer 10. In the magnetization M of the second ferromagnetic layer 3030 In this case, even when a sufficient external force is applied to reverse the magnetization of the third magnetization region A3, the magnetization M of the second ferromagnetic layer 30 30 does not change in direction, and the magnetization M 30 is fixed. The second ferromagnetic layer 30 may be referred to as a fixed layer or a reference layer.

[0054] The second ferromagnetic layer 30 contains a ferromagnetic material. The second ferromagnetic layer 30 contains, for example, a material that easily achieves a coherent tunneling effect between the second ferromagnetic layer 30 and the first ferromagnetic layer 10. The second ferromagnetic layer 30 contains, for example, a metal selected from the group consisting of Cr, Mn, Co, Fe, and Ni, an alloy containing one or more of these metals, an alloy containing these metals and at least one or more elements B, C, and N, etc. The second ferromagnetic layer 30 is made of, for example, Co—Fe, Co—Fe—B, or Ni—Fe. In addition, the second ferromagnetic layer 30 may have a stacked film of Co and Ni, a stacked film of Co and Pt, or a stacked film of Co and Pd.

[0055] The second ferromagnetic layer 30 may be, for example, a Heusler alloy. A Heusler alloy is a half-metal and has a high spin polarization. A Heusler alloy is an intermetallic compound having a chemical composition of XYZ or X2YZ, where X is a transition metal element or a noble metal element in the Co, Fe, Ni, or Cu group in the periodic table, Y is a transition metal element in the Mn, V, Cr, or Ti group in the periodic table or an element of the same type as X, and Z is a typical element in Groups III to V in the periodic table. A Heusler alloy is, for example, Co2FeSi, Co2FeGe, Co2FeGa, Co2MnSi, Co2Mn 1-a Fe a Al b Si 1-b , Co2FeGe 1-c Ga c , etc.

[0056] The second ferromagnetic layer 30 may have a plurality of layers and may have a synthetic antiferromagnetic structure (SAF structure). The synthetic antiferromagnetic structure is composed of two magnetic layers and a nonmagnetic spacer layer interposed therebetween. The magnetic layer contains, for example, a ferromagnetic material and may contain an antiferromagnetic material such as IrMn or PtMn. The spacer layer contains, for example, at least one selected from the group consisting of Ru, Ir, and Rh.

[0057] For example, each of the second ferromagnetic layer 30 and the nonmagnetic layer 20 is longer than the third magnetization region A3 in the x direction. The portions where the second ferromagnetic layer 30 and the third magnetization region A3 face each other with the nonmagnetic layer 20 therebetween are the cause of the resistance change of the domain wall movement element 100. When the length of the third magnetization region of the first ferromagnetic layer 10 in the x direction is long, the resistance change of the domain wall movement element 100 becomes gentler, and the width of the resistance change of the domain wall movement element 100 can be more easily divided into multiple values. Further, when the ratio of the third magnetization region A3 of the first ferromagnetic layer 10 is larger than the ratios of the first magnetization region A1 and the second magnetization region A2, the width of the resistance change of the domain wall movement element 100 can be made larger, which makes detection easier.

[0058] The second ferromagnetic layer 30 is, for example, longer than the first ferromagnetic layer 10 in the x direction. When the second ferromagnetic layer 30 overlaps the entire first ferromagnetic layer 10 when viewed in the z direction, the heat dissipation property of the first ferromagnetic layer 10 is improved. Accordingly, the stability of the magnetization of the first magnetization region A1 and the magnetization of the second magnetization region A2 is enhanced, and the reliability of the data of the domain wall movement element 100 is enhanced.

[0059] The first magnetization fixing portion 40 is connected to the first ferromagnetic layer 10. The first magnetization fixing portion 40 is connected to the first magnetization region A1. The first magnetization fixing portion 40 fixes the magnetization M of the first magnetization region A1 A1 . The shape of the first magnetization fixing portion 40 in the plan view is not particularly limited. The shape of the first magnetization fixing portion 40 in the plan view may be, for example, a rectangle as shown in Figure 5 or may be a circle.

[0060] Figure 6 is a cross-sectional view of the first magnetization fixing portion 40 according to the first embodiment. The first magnetization fixing portion 40 includes a first magnetization fixing layer 41, a first nonmagnetic layer 42, and a second magnetization fixing layer 43.

[0061] The first magnetization fixing layer 41 and the second magnetization fixing layer 43 are antiferromagnetically coupled to each other, and the first nonmagnetic layer 42 is interposed between the first magnetization fixing layer 41 and the second magnetization fixing layer 43. Here, the antiferromagnetic coupling is caused by the magnetization of the entire second magnetization fixing layer 43 and the magnetization of the first magnetization fixing layer 41. The magnetic coupling occurs through the RKKY interaction.

[0062] The first magnetization fixing layer 41 is in contact with the first ferromagnetic layer 10. An intermediate layer may be provided between the first magnetization fixing layer 41 and the first ferromagnetic layer 10, and the thickness of the intermediate layer maintains the magnetic coupling between the first magnetization fixing layer 41 and the first ferromagnetic layer 10. The first magnetization fixing layer 41 is made of a ferromagnetic material. The first magnetization fixing layer 41 is a single layer. For example, the same material as the first ferromagnetic layer 10 or the second ferromagnetic layer 30 may be used as the first magnetization fixing layer 41.

[0063] The first nonmagnetic layer 42 is located between the first magnetization fixing layer 41 and the second magnetization fixing layer 43 in the z direction. The first nonmagnetic layer 42 is in contact with the first magnetization fixing layer 41. The first nonmagnetic layer 42 contains, for example, a nonmagnetic metal, alloy, or compound. The first nonmagnetic layer 42 is made of, for example, a metal, alloy, or compound containing an element with an atomic number of 39 or higher. The first nonmagnetic layer 42 is made of, for example, Ru, Ir, or Rh.

[0064] The second magnetization fixing layer 43 has a first anti-diffusion structure 46. The second magnetization fixing layer 43 includes, for example, a first layer 45 containing a ferromagnetic material, a first anti-diffusion structure 46, and a second layer 47 containing a ferromagnetic material. The second layer 47 is an example of a second region.

[0065] The second magnetization fixing layer 43 as a whole exhibits ferromagnetism. The overall magnetization of the second magnetization fixing layer 43 is the sum of the magnetizations of the ferromagnetic materials constituting the second magnetization fixing layer 43. For example, the overall magnetization of the second magnetization fixing layer 43 is the sum of the magnetization of the first layer 45, the magnetization of the ferromagnetic material constituting the first anti-diffusion structure 46, and the magnetization of the second layer 47.

[0066] The first layer 45 is in contact with the first nonmagnetic layer 42. The first layer 45 contains a ferromagnetic material. For example, the same material as the first ferromagnetic layer 10 or the second ferromagnetic layer 30 may be used as the first layer 45. The magnetization M of the first layer 45 45 and the magnetization M of the first magnetization fixing layer 41 41 are antiferromagnetically coupled to each other. The magnetic coupling occurs through the RKKY interaction.

[0067] The second layer 47 is in contact with the first electrode E1. The second layer 47 contains a ferromagnetic material. For example, the same material as the first ferromagnetic layer 10 or the second ferromagnetic layer 30 may be used as the second layer 47. Preferably, the magnetization M of the second layer 47 47 is oriented in the same direction as the magnetization M of the first layer 45. 45 When the second layer 47 and the first layer 45 have the same magnetization orientation direction, the saturation magnetization of the entire second magnetization fixing layer 43 increases, and the magnetization stability of the entire second magnetization fixing layer 43 increases.

[0068] The first anti-diffusion structure 46 is located between the first layer 45 and the second layer 47 in the z direction. The first anti-diffusion structure 46 may have a single layer or multiple layers. Figure 6 The case where the first anti-diffusion structure 46 has multiple layers is shown.

[0069] The first anti-diffusion structure 46 includes, for example, a plurality of intermediate ferromagnetic layers 48A, 48B, 48C, 48D, and 48E and a plurality of intermediate non-magnetic layers 49A, 49B, 49C, 49D, 49E, and 49F. Each of the intermediate ferromagnetic layers is interposed between the intermediate non-magnetic layers in the z direction.

[0070] There is no particular limitation on the number of the intermediate ferromagnetic layers and the intermediate non-magnetic layers in the first anti-diffusion structure 46. When adjacent intermediate ferromagnetic layers are antiferromagnetically coupled to each other and the number of the intermediate ferromagnetic layers is odd, the main directions of the magnetization orientation directions of the first layer 45 and the second layer 47 are the same.

[0071] The magnetization M of the intermediate ferromagnetic layer 48A 48A is antiferromagnetically coupled to the magnetization M of the first layer 45. 45 The magnetization M of the intermediate ferromagnetic layer 48A 48A is antiferromagnetically coupled to the magnetization M of the intermediate ferromagnetic layer 48B. 48B The magnetization M of the intermediate ferromagnetic layer 48B 48B is antiferromagnetically coupled to the magnetization M of the intermediate ferromagnetic layer 48C. 48C The magnetization M of the intermediate ferromagnetic layer 48C 48C is antiferromagnetically coupled to the magnetization M of the intermediate ferromagnetic layer 48D. 48D The magnetization M of the intermediate ferromagnetic layer 48D 48D is antiferromagnetically coupled to the magnetization M of the intermediate ferromagnetic layer 48E. 48E The first anti-diffusion structure 46 may internally include a plurality of ferromagnetic layers that are antiferromagnetically coupled to each other. When the ferromagnetic layers constituting the first anti-diffusion structure 46 are antiferromagnetically coupled to each other, the leakage magnetic field from the first anti-diffusion structure 46 becomes smaller. The magnetic coupling occurs through the RKKY interaction.

[0072] For example, the same material as that of the first ferromagnetic layer 10 or the second ferromagnetic layer 30 may be used for each of the intermediate ferromagnetic layers 48A, 48B, 48C, 48D, and 48E. For example, the thickness of each of the intermediate ferromagnetic layers 48A, 48B, 48C, 48D, and 48E is smaller than the thickness of each of the first layer 45 and the second layer 47.

[0073] The same material as the first non-magnetic layer 42 can be used for each of the intermediate non-magnetic layers 49A, 49B, 49C, 49D, 49E, and 49F. Each of the intermediate non-magnetic layers 49A, 49B, 49C, 49D, 49E, and 49F is made of, for example, a metal, alloy, or compound containing an element with an atomic number of 39 or higher. Heavy elements with an atomic number of 39 or higher can prevent element diffusion. Each of the intermediate non-magnetic layers 49A, 49B, 49C, 49D, 49E, and 49F can be a metal film, oxide film, nitride film, etc. containing Ta, Ti, Al, or Si, or can be a noble metal film.

[0074] The total thickness of the non-magnetic layers included in the first anti-diffusion structure 46 is preferably 50 Å or greater, and more preferably 100 Å or greater. In Figure 6 the example shown, the total thickness of the intermediate non-magnetic layers 49A, 49B, 49C, 49D, 49E, and 49F corresponds to the total thickness of the non-magnetic layers included in the first anti-diffusion structure 46. The thickness of each of the intermediate non-magnetic layers 49A, 49B, 49C, 49D, 49E, and 49F is the thickness at which adjacent intermediate ferromagnetic layers are antiferromagnetically coupled to each other through, for example, the RKKY interaction.

[0075] The second magnetization fixing portion 50 is connected to the first ferromagnetic layer 10 at a position separated from the first magnetization fixing portion 40 in the x direction. The second magnetization fixing portion 50 is connected to the second magnetization region A2. The second magnetization fixing portion 50 fixes the magnetization M A2 of the second magnetization region A2. The shape of the second magnetization fixing portion 50 in the plan view can be, for example, a rectangle as Figure 5 shown, or can be circular.

[0076] Figure 7 is a cross-sectional view of the second magnetization fixing portion 50 according to the first embodiment. The second magnetization fixing portion 50 includes a third magnetization fixing layer 51, a second non-magnetic layer 52, and a fourth magnetization fixing layer 53.

[0077] The third magnetization fixing layer 51 and the fourth magnetization fixing layer 53 are antiferromagnetically coupled to each other, and the second non-magnetic layer 52 is interposed between the third magnetization fixing layer 51 and the fourth magnetization fixing layer 53. Here, the antiferromagnetic coupling is caused by the magnetization of the entire fourth magnetization fixing layer 53 and the magnetization of the third magnetization fixing layer 51. The magnetic coupling occurs through the RKKY interaction.

[0078] The third magnetization fixing layer 51 is in contact with the first ferromagnetic layer 10. An intermediate layer may be provided between the third magnetization fixing layer 51 and the first ferromagnetic layer 10, and the thickness of the intermediate layer maintains the magnetic coupling between the third magnetization fixing layer 51 and the first ferromagnetic layer 10. The third magnetization fixing layer 51 is made of a ferromagnetic material. The third magnetization fixing layer 51 is a single layer. For example, the same material as the first ferromagnetic layer 10 or the second ferromagnetic layer 30 may be used as the third magnetization fixing layer 51. The thickness of the third magnetization fixing layer 51 is the same as the thickness of the first magnetization fixing layer 41.

[0079] The second non-magnetic layer 52 is located between the third magnetization fixing layer 51 and the fourth magnetization fixing layer 53 in the z direction. The second non-magnetic layer 52 is in contact with the third magnetization fixing layer 51. The same material as the first non-magnetic layer 42 may be used for the second non-magnetic layer 52. The thickness of the second non-magnetic layer 52 is the same as the thickness of the first non-magnetic layer 42.

[0080] The fourth magnetization fixing layer 53 has a second anti-diffusion structure 56. The fourth magnetization fixing layer 53 includes, for example, a third layer 55 containing a ferromagnetic material, a second anti-diffusion structure 56, and a fourth layer 57 containing a ferromagnetic material. The fourth layer 57 is an example of the first region.

[0081] The fourth magnetization fixing layer 53 as a whole exhibits ferromagnetism. The overall magnetization of the fourth magnetization fixing layer 53 is the sum of the magnetizations of the ferromagnetic materials constituting the fourth magnetization fixing layer 53. For example, the overall magnetization of the fourth magnetization fixing layer 53 is the sum of the magnetization of the third layer 55, the magnetization of the ferromagnetic material constituting the second anti-diffusion structure 56, and the magnetization of the fourth layer 57.

[0082] The third layer 55 is in contact with the second non-magnetic layer 52. The third layer 55 contains a ferromagnetic material. For example, the same material as the first ferromagnetic layer 10 or the second ferromagnetic layer 30 may be used as the third layer 55. The magnetization M 55 of the third layer 55 and the magnetization M 51 of the third magnetization fixing layer 51 are antiferromagnetically coupled to each other. The magnetic coupling occurs through the RKKY interaction.

[0083] The fourth layer 57 is in contact with the second electrode E2. The position of the fourth layer 57 is further away from the second non-magnetic layer 52 than the second anti-diffusion structure 56. The fourth layer 57 contains a ferromagnetic element and a non-magnetic element. The fourth layer 57 is a layer obtained by ion-implanting non-magnetic element ions into a ferromagnetic layer. By ion-implanting non-magnetic element ions into the ferromagnetic layer, the saturation magnetization of the fourth layer 57 is less than the saturation magnetization of the second layer 47. The fourth layer 57 may be non-magnetic as a whole.

[0084] The ferromagnetic element constituting the fourth layer 57 is the same as the ferromagnetic element contained in the second layer 47.

[0085] The non-magnetic element constituting the fourth layer 57 is, for example, a noble gas. Since the atomic radius of a noble gas is larger than that of other elements, it can disrupt the magnetization alignment of the ferromagnetic material and reduce the saturation magnetization of the fourth layer 57. The noble gas can be, for example, He, Ar, Kr, or Xe, and can be one type or two types or multiple types.

[0086] The non-magnetic element constituting the fourth layer 57 can be at least one element selected from the group consisting of B, N, O, F, and Ga. Preferably, the non-magnetic element constituting the fourth layer 57 is at least one element selected from the group consisting of N, O, F, and Ga. Elements such as N, O, F, and Ga with an atomic weight greater than B have greater kinetic energy during ion implantation and can be implanted deeper. Therefore, using these elements is beneficial for processing by element implantation.

[0087] The non-magnetic element constituting the fourth layer 57 is, for example, an element not contained in the second layer 47.

[0088] The second anti-diffusion structure 56 is located between the third layer 55 and the fourth layer 57 in the z direction. The second anti-diffusion structure 56 can have a single layer or multiple layers. Figure 7 The case where the second anti-diffusion structure 56 has multiple layers is shown. The second anti-diffusion structure 56 prevents the non-magnetic element contained in the fourth layer 57 from diffusing into the third layer 55. In the case where the second anti-diffusion structure 56 is composed of multiple layers including a ferromagnetic layer and a non-magnetic layer, the non-magnetic element contained in the fourth layer 57 can be prevented from diffusing into the third layer 55.

[0089] The second anti-diffusion structure 56 includes, for example, multiple intermediate ferromagnetic layers 58A, 58B, 58C, 58D, and 58E and multiple intermediate non-magnetic layers 59A, 59B, 59C, 59D, 59E, and 59F. Each of the intermediate ferromagnetic layers is located between the intermediate non-magnetic layers in the z direction.

[0090] The number of the intermediate ferromagnetic layers and the intermediate non-magnetic layers in the second anti-diffusion structure 56 is the same as the number of the intermediate ferromagnetic layers and the intermediate non-magnetic layers in the first anti-diffusion structure 46.

[0091] The second anti-diffusion structure 56 can include multiple ferromagnetic layers that are antiferromagnetically coupled to each other inside.

[0092] The structure of each of the intermediate ferromagnetic layers 58A, 58B, 58C, 58D, and 58E is the same as the structure of each of the intermediate ferromagnetic layers 48A, 48B, 48C, 48D, and 48E.

[0093] Each of the intermediate nonmagnetic layers 59A, 59B, 59C, 59D, 59E, and 59F has the same structure as each of the intermediate nonmagnetic layers 49A, 49B, 49C, 49D, 49E, and 49F. Each of the intermediate nonmagnetic layers 59A, 59B, 59C, 59D, 59E, and 59F is made of, for example, a metal, an alloy, or a compound containing an element with an atomic number of 39 or higher.

[0094] The total thickness of the nonmagnetic layers included in the second anti-diffusion structure 56 is preferably 50 Å or greater, and more preferably 100 Å or greater. In Figure 7 the illustrated example, the total thickness of the intermediate nonmagnetic layers 59A, 59B, 59C, 59D, 59E, and 59F corresponds to the total thickness of the nonmagnetic layers included in the second anti-diffusion structure 56. When the total thickness of the nonmagnetic layers included in the second anti-diffusion structure 56 is large enough, diffusion of the nonmagnetic elements contained in the fourth layer 57 into the third layer 55 can be further prevented. Desirably, the concentration of the nonmagnetic elements contained in the second anti-diffusion structure 56 is lower on the side closer to the third layer 55 than on the side closer to the fourth layer 57.

[0095] Here, the positional relationship between the first magnetization fixing portion 40 and the second magnetization fixing portion 50 is not limited to Figure 4 the illustrated example. The positional relationship between the first magnetization fixing portion 40 and the second magnetization fixing portion 50 can be reversed, and the first magnetization fixing portion 40 can be located at the +x direction position of the second magnetization fixing portion 50.

[0096] The first electrode E1 is connected to the first magnetization fixing portion 40. The first electrode E1 can be in direct contact with the first magnetization fixing portion 40, or can be indirectly connected to the first magnetization fixing portion 40 via an intervening layer. The first electrode E1 is, for example, a write electrode used when applying a write current to the magnetic domain wall movement element 100. The write current flows between the first electrode E1 and the second electrode E2. The first electrode E1 contains a conductive material.

[0097] The second electrode E2 is connected to the second magnetization fixing portion 50. The second electrode E2 can be in direct contact with the second magnetization fixing portion 50, or can be indirectly connected to the second magnetization fixing portion 50 via an intervening layer. The second electrode E2 is a common electrode used when applying a write current to the magnetic domain wall movement element 100 and when applying a read current to the magnetic domain wall movement element 100. The second electrode E2 contains a conductive material.

[0098] The third electrode E3 is connected to the second ferromagnetic layer 30. The third electrode E3 may be in direct contact with the second ferromagnetic layer 30 or may be indirectly connected to the second ferromagnetic layer 30 via an intervening layer. The third electrode E3 is a read electrode used when applying a read current to the magnetic domain wall movement element 100. The third electrode E3 contains a conductive material.

[0099] The magnetic domain wall movement element 100 may have layers other than the above-mentioned layers. Further, for example, a magnetic layer may be provided on the surface of the second ferromagnetic layer 30 on the side opposite to the non-magnetic layer 20 via a spacer layer. The second ferromagnetic layer 30, the spacer layer, and the magnetic layer form a synthetic antiferromagnetic structure (SAF structure). Further, a bottom layer may be provided on the surface of the magnetic layer on the side opposite to the spacer layer.

[0100] For example, the magnetization direction of each layer of the magnetic domain wall movement element 100 can be examined by measuring the magnetization curve. The magnetization curve can be measured using, for example, the magneto-optical Kerr effect (MOKE). The measurement using MOKE is a measurement method in which linearly polarized light is incident on an object to be measured and the magneto-optical effect (magnetic Kerr effect) such as the rotation of its polarization direction is utilized.

[0101] The manufacturing method of the magnetic domain wall movement element 100 includes: a stacking step of each layer; a processing step of processing a part of each layer into a predetermined shape; and an element injection step of injecting a non-magnetic element into a part of the magnetization fixing portion.

[0102] In the stacking step, the layer that will become the second ferromagnetic layer 30, the layer that will become the non-magnetic layer 20, the layer that will become the first ferromagnetic layer 10, the layer that will become the first magnetization fixing layer 41 and the third magnetization fixing layer 51, the layer that will become the first non-magnetic layer 42 and the second non-magnetic layer 52, the layer that will become the first layer 45 and the third layer 55, the layer that will become the first anti-diffusion structure 46 and the second anti-diffusion structure 56, and the layer that will become the second layer 47 and the fourth layer 57 are sequentially stacked on the third electrode E3. For the stacking of each layer, a sputtering method, a chemical vapor deposition (CVD) method, an electron beam vapor deposition method (EB vapor deposition method), an atomic laser deposition method, etc. can be used.

[0103] In the processing step, a part of the stack stacked in the stacking step is processed. The processing of the stack can be performed using photolithography, etching (e.g., Ar etching or reactive ion etching), etc.

[0104] The processing step includes an outer shape forming step and a magnetization fixing portion forming step.

[0105] In the outer shape forming step, the outer shape of the stack is determined.

[0106] In the magnetization fixing portion forming step, the layers of the stack that will become the magnetization fixing portion are processed. The layers that will become the magnetization fixing portion are the layers that will become the first magnetization fixing layer 41 and the third magnetization fixing layer 51, the layers that will become the first non-magnetic layer 42 and the second non-magnetic layer 52, the layers that will become the first layer 45 and the third layer 55, the layers that will become the first anti-diffusion structure 46 and the second anti-diffusion structure 56, and the layers that will become the second layer 47 and the fourth layer 57. By processing these layers to separate them in the x direction, two magnetization fixing portions are formed on the first ferromagnetic layer 10.

[0107] In the element injection step, a non-magnetic element is injected into one of the ferromagnetic layers of the two magnetization fixing portions. For example, a non-magnetic element is injected into the ferromagnetic layer located at the position corresponding to the fourth layer 57. The non-magnetic element can be injected by known methods. For example, ion implantation, plasma doping, laser doping, etc. are some of the methods for doping non-magnetic elements into ferromagnetic materials. The ferromagnetic layer located at the position corresponding to the fourth layer 57 is doped with a non-magnetic element, and thus its saturation magnetization decreases. As the saturation magnetization of the fourth layer 57 becomes smaller, a difference in coercive force is generated between the first magnetization fixing portion 40 and the second magnetization fixing portion 50. Using this coercive force difference, the magnetization M 41 of the first magnetization fixing layer 41 and the magnetization M 51 of the third magnetization fixing layer 51 can be made to face in opposite directions.

[0108] In the case of etching a part of the magnetization fixing portion to generate a coercive force difference, the progress of the etching may vary. In contrast, in the magnetic domain wall movement element 100 according to the present embodiment, a coercive force difference can be generated without performing etching.

[0109] Next, the write operation of the signal to the magnetic array MA and the read operation of the signal from the magnetic array MA will be described.

[0110] First, the write operation of the signal to the magnetic array MA will be described. The write operation is performed, for example, by a processor executing an operation program stored in the control component 6.

[0111] First, the control device 3 selects the magnetic domain wall movement element 100 to which a pulse is applied according to the operation program. In the case where the magnetic array MA is used as a magnetic memory, the magnetic domain wall movement element 100 to which a pulse is applied is the element that stores data. In the case where the magnetic array MA is used as a neural network, the magnetic domain wall movement element 100 to which a pulse is applied is the element that changes the weights according to learning.

[0112] The control unit 6 controls which of the plurality of domain wall movement elements 100 the pulse is applied to. The control unit 6 turns on the first switch SW1 and the second switch SW2 connected to the domain wall movement element 100 to which the pulse is applied, and turns off the third switch SW3. Further, at least one of the first switch SW1 and the second switch SW2 connected to the domain wall movement element 100 to which no pulse is applied is turned off.

[0113] Then, the control device 3 outputs a write pulse to the domain wall movement element 100 according to the operation program. A write pulse is applied between the first magnetization fixing portion 40 and the second magnetization fixing portion 50 along the first ferromagnetic layer 10 of the domain wall movement element 100. The write pulse can be a rectangular wave, a spike wave, or a wave of any other waveform. By changing the number, amplitude, etc. of the write pulse, the position of the domain wall DW changes, and a signal is written to a specific domain wall movement element 100.

[0114] Next, the read operation of the signal from the magnetic array MA will be described. For example, the read operation is performed by a processor executing the operation program stored in the control unit 6.

[0115] First, the control device 3 selects the domain wall movement element 100 to which the read pulse is applied according to the operation program. When the magnetic array MA is used as a magnetic memory, the domain wall movement element 100 to which the read pulse is applied is the element for reading data. When the magnetic array MA is used as a neural network, applying the read pulse to a predetermined domain wall movement element 100 corresponds to the calculation of the product of the input and the weight. That is, when the magnetic array MA is used as a neural network, the read operation is the recognition calculation of the neural network.

[0116] The control unit 6 controls which of the plurality of domain wall movement elements 100 the pulse is applied to. The control unit 6 turns on the third switch SW3 and the second switch SW2 connected to the domain wall movement element 100 to which the pulse is applied, and turns off the first switch SW1. Further, at least one of the third switch SW3 and the second switch SW2 connected to the domain wall movement element 100 to which no pulse is applied is turned off.

[0117] Next, the control device 3 applies a read pulse to a predetermined domain wall movement element 100 according to the operation program. For example, the read pulse is applied between the third wiring W3 and the first magnetization fixing portion 40. The voltage of the read pulse is the voltage when a current density lower than the critical current density required to move the domain wall DW of the first ferromagnetic layer 10 is obtained. That is, the read pulse does not move the domain wall DW.

[0118] The resistance detection device 4 detects the resistance value of the magnetic domain wall movement element 100 to which a read pulse is applied. For example, the output component 5 outputs the calculation result to the outside. Through such a process, a signal can be read from a specific magnetic domain wall movement element 100.

[0119] In the magnetic domain wall movement element 100 according to the present embodiment, by doping a non-magnetic element into a part of the ferromagnetic layer, a coercivity difference is generated between the first magnetization fixing portion 40 and the second magnetization fixing portion 50. In the case of using etching to generate the coercivity difference, it is necessary to control the progress of the etching, but in the manufacturing method of the magnetic domain wall movement element 100 according to the present embodiment, such control is not required.

[0120] In addition, since the magnetic domain wall movement element 100 according to the present embodiment has the second anti-diffusion structure 56, the doping range of the non-magnetic element can be restricted. Therefore, in the magnetic domain wall movement element 100 according to the present embodiment, the magnetization stability of the first ferromagnetic layer 10 can be controlled to an expected value. The magnetic domain wall movement element 100 with high magnetization stability has excellent operation stability and highly reliable stored data.

[0121] In addition, in the case where a plurality of magnetic domain wall movement elements 100 are provided in the integration region 1, the anti-diffusion structure can be used to define the range of diffusion of the non-magnetic element, so that the change in the magnetization state of each element can be reduced. The magnetic array in which the plurality of magnetic domain wall movement elements 100 provided in the integration region 1 have less change has highly versatile and highly reliable output signals.

[0122] The magnetic domain wall movement element 100 according to the first embodiment can be used for, for example, a magnetic memory or a neuromorphic device.

[0123] In the case of a magnetic memory, each of the magnetic domain wall movement elements 100 serves as an element for storing data. The resistance of the magnetic domain wall movement element 100 changes at the position of the domain wall DW of the magnetic domain wall movement element 100, and this resistance value is stored as data.

[0124] In the case of a neuromorphic device, each of the magnetic domain wall movement elements 100 serves as a product calculation element. The resistance of the magnetic domain wall movement element 100 changes at the position of the domain wall DW of the magnetic domain wall movement element 100, and this resistance value represents a weight.

[0125] A neuromorphic device is a device that artificially imitates the relationship between neurons and synapses in the human brain. The neuromorphic device can perform the calculation of a neural network.

[0126] Figure 8 is a schematic diagram of the neural network NN. The neural network NN has an input layer L in , an intermediate layer L m and an output layer Lout 。 Figure 8 illustrates an example with three intermediate layers L m , but the number of intermediate layers L m is not limited. Each of the input layer L in , intermediate layer L m and output layer L out has multiple nodes N, and each node N corresponds to a neuron in the brain. The input layer L in , intermediate layer L m and output layer L out are connected by a transmission device. The transmission device corresponds to a synapse in the brain. Figure 8 The number of nodes N and transmission devices shown in Figure 8 illustrates an example in which the input layer L in is composed of two nodes, but the number of nodes constituting the input layer L in , intermediate layer L m and output layer L out is not limited.

[0127] The neural network NN learns through a transmission device (synapse) to increase the percentage of correct answers to a problem. Learning is to find knowledge that can be used in the future from information. The neural network NN learns by operating while changing the weights of the transmission device. The transmission device performs a product calculation to apply the weights to the input signal and a summation calculation to add the results of the product calculation. That is, the transmission device performs a product and summation calculation. The domain wall motion element 100 according to the present embodiment is responsible for this product calculation.

[0128] Figure 9 is a block diagram showing a system 300 including a neuromorphic device 200 according to the first embodiment. The system 300 has a plurality of sensors 201, a neuromorphic device 200, and a communication component 202.

[0129] Each of the plurality of sensors 201 can be any sensor suitable for the application. For example, a temperature sensor, a humidity sensor, a speed sensor, a pressure sensor, an acceleration sensor, etc. can be used as the plurality of sensors 201. Signals from these sensors, for example, correspond to the signals input to the input layer L in of the neural network NN.

[0130] The neuromorphic device 200, for example, has a plurality of integration regions 1. In each integration region 1, a product and summation calculation is performed. Each of the integration regions 1 performs a calculation from each layer of the neural network NN to the next layer. Each of the integration regions 1 can have a separate control device 3, or can share the control device 3.

[0131] The conductance (or resistance) of the domain wall motion element 100 changes according to the position of the domain wall DW. The conductance (or resistance) of the domain wall motion element 100 corresponds to the weight of the transmission device in the neural network NN. The conductance (or resistance) of the domain wall motion element 100 changes linearly with respect to the input. For example, in a case where information (such as temperature) of a specific sensor 201 among a plurality of sensors 201 is crucial, when the neuromorphic device 200 learns, the conductance (weight) of the domain wall motion element 100 responsible for propagating signals from this sensor 201 increases.

[0132] The domain wall motion element 100 outputs the product of the input voltage and the conductance (or resistance) of the domain wall motion element 100 as a signal, and thus serves as a product calculation element. The magnetic array MA combines the outputs of a plurality of domain wall motion elements 100, and thus serves as a product and summation calculation device. The product and summation calculation of the plurality of domain wall motion elements 100 is controlled by the control device 3.

[0133] The neuromorphic device 200 performs learning and inference. During learning, the conductance of the domain wall motion element 100 (corresponding to the weight of the transmission device) is adjusted. Inference is performed using the set conductance of the domain wall motion element 100 (corresponding to the weight of the transmission device).

[0134] The neuromorphic device 200 used in the system 300 may be capable of performing both learning and inference, or may only perform inference. In the case of only performing inference, learning applicable to the task is performed in advance, and weights applicable to the task are installed in the domain wall motion elements 100 of the neuromorphic device 200. For example, the conductance of each domain wall motion element 100 is adjusted to correspond to the weight of the transmission device determined by pre-learning. If the neuromorphic device 200 only performs inference, the computational load on the edge device can be reduced.

[0135] The communication component 202 outputs the calculation result of the neuromorphic device 200 to the outside. For example, the inference result for a predetermined task obtained by the neuromorphic device 200 is input to the communication component 202, and the communication component 202 outputs this information to the outside. The communication component 202 can be wired or wireless.

[0136] The change of each element of the domain wall motion element 100 according to this embodiment is small and has excellent operation stability, so the system 300 has high reliability.

[0137] Although the preferred embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to this embodiment.

[0138] For example, although an example is shown in which the ferromagnetic layers constituting the first anti-diffusion structure 46 and the second anti-diffusion structure 56 are antiferromagnetically coupled to each other, these ferromagnetic layers may also be ferromagnetically coupled to each other.

[0139] Furthermore, although an example is shown in which the first anti-diffusion structure 46 and the second anti-diffusion structure 56 are composed of multiple layers, the first anti-diffusion structure 46 and the second anti-diffusion structure 56 may also have a single layer. That is, the first anti-diffusion structure 46 may be a single-layer first anti-diffusion layer, and the second anti-diffusion structure 56 may be a single-layer second anti-diffusion layer.

[0140] The number of ferromagnetic layers and non-magnetic layers constituting the first magnetization fixing portion and the second magnetization fixing portion is not limited to these examples and is arbitrary. Furthermore, the domain wall movement element does not necessarily have the non-magnetic layer 20 and the second ferromagnetic layer 30. In this case, the domain wall movement element is used as a magneto-optical element, for example.

[0141] Reference numerals:

[0142] 1 Integration region

[0143] 2 Peripheral region

[0144] 3 Control device

[0145] 4 Resistance detection device

[0146] 5 Output component

[0147] 6 Control component

[0148] 7 Power supply

[0149] 10 First ferromagnetic layer

[0150] 20 Non-magnetic layer

[0151] 30 Second ferromagnetic layer

[0152] 40 First magnetization fixing portion

[0153] 41 First magnetization fixing layer

[0154] 42 First non-magnetic layer

[0155] 43 Second magnetization fixing layer

[0156] 45 First layer

[0157] 46 First anti-diffusion structure

[0158] 47 Second layer (second region)

[0159] Intermediate ferromagnetic layers of 48A, 48B, 48C, 48D, 48E, 58A, 58B, 58C, 58D, 58E

[0160] Intermediate non-magnetic layers of 49A, 49B, 49C, 49D, 49E, 49F, 59A, 59B, 59C, 59D, 59E, 59F

[0161] 50 Second magnetization fixing part

[0162] 51 Third magnetization fixing layer

[0163] 52 Second non-magnetic layer

[0164] 53 Fourth magnetization fixing layer

[0165] 55 Third layer

[0166] 56 Second anti-diffusion structure

[0167] 57 Fourth layer (first region)

[0168] 90 Insulating layer

[0169] 100 Magnetic domain wall motion element

[0170] 200 Neuromorphic device

[0171] 201 Sensor

[0172] 202 Communication component

[0173] 300 System

[0174] E1 First electrode

[0175] E2 Second electrode

[0176] E3 Third electrode

[0177] MA Magnetic array

Claims

1. A magnetic domain wall motion element, comprising: A first ferromagnetic layer having a domain wall therein; A first magnetization fixing portion connected to the first ferromagnetic layer; And A second magnetization fixing portion connected to the first ferromagnetic layer at a position separated from the first magnetization fixing portion, Wherein the first magnetization fixing portion includes a first magnetization fixing layer, a first non-magnetic layer, and a second magnetization fixing layer, The first magnetization fixing layer and the second magnetization fixing layer are antiferromagnetically coupled to each other, and the first non-magnetic layer is interposed between the first magnetization fixing layer and the second magnetization fixing layer, The first magnetization fixing layer is in contact with the first ferromagnetic layer, The first non-magnetic layer is located between the first magnetization fixing layer and the second magnetization fixing layer in the stacking direction, The second magnetization fixing layer has a first anti-diffusion structure, The second magnetization fixing portion includes a third magnetization fixing layer, a second non-magnetic layer, and a fourth magnetization fixing layer, The third magnetization fixing layer and the fourth magnetization fixing layer are antiferromagnetically coupled to each other, and the second non-magnetic layer is interposed between the third magnetization fixing layer and the fourth magnetization fixing layer, The third magnetization fixing layer is in contact with the first ferromagnetic layer, The second non-magnetic layer is located between the third magnetization fixing layer and the fourth magnetization fixing layer in the stacking direction, The fourth magnetization fixing layer has a second anti-diffusion structure and a first region, The first region is located at a position further away from the second non-magnetic layer than the second anti-diffusion structure, and The first region contains a ferromagnetic element and a non-magnetic element.

2. The domain wall movement element according to claim 1, wherein The first anti-diffusion structure includes a plurality of ferromagnetic layers antiferromagnetically coupled to each other therein.

3. The domain wall movement element according to claim 1, wherein, The first anti-diffusion structure includes a plurality of ferromagnetic layers ferromagnetically coupled to each other therein.

4. The magnetic domain wall displacement element according to claim 1, wherein The second anti-diffusion structure includes a plurality of ferromagnetic layers antiferromagnetically coupled to each other therein.

5. The magnetic domain wall motion element according to claim 1, wherein The second anti-diffusion structure includes a plurality of ferromagnetic layers ferromagnetically coupled to each other therein.

6. The magnetic domain wall motion element according to claim 1, wherein The first anti-diffusion structure has an intermediate non-magnetic layer therein, and The intermediate non-magnetic layer contains an element with an atomic number of 39 or higher.

7. The magnetic domain wall motion element according to claim 1, wherein The second anti-diffusion structure has an intermediate non-magnetic layer therein, and The intermediate non-magnetic layer contains an element with an atomic number of 39 or higher.

8. The domain wall movement element according to claim 1, wherein, The non-magnetic element contained in the first region is a noble gas.

9. The magnetic domain wall movement element according to claim 1, wherein The non-magnetic element contained in the first region is at least one element selected from the group consisting of B, N, O, F, and Ga.

10. The magnetic domain wall motion element according to claim 1, wherein The second magnetization fixing layer further includes a second region, and The saturation magnetization of the first region is less than the saturation magnetization of the second region.

11. The magnetic domain wall motion element according to claim 1, wherein Each of the first anti-diffusion structure and the second anti-diffusion structure has one or more intermediate non-magnetic layers therein, and The number of intermediate non-magnetic layers included in the first anti-diffusion structure is the same as the number of intermediate non-magnetic layers included in the second anti-diffusion structure.

12. The magnetic domain wall movement element according to claim 1, further comprising a third non-magnetic layer and a second ferromagnetic layer, Among them, The third non-magnetic layer is interposed between the first ferromagnetic layer and the second ferromagnetic layer in the stacking direction.

13. A magnetic array comprising a plurality of magnetic domain wall movement elements, Among them, Each of the plurality of magnetic domain wall movement elements is the magnetic domain wall movement element according to claim 1.

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