Magnetic nanowire memory

Abstract

To provide a magnetic nanowire memory including a reproduction element suitable for reproducing binary information accumulated in magnetic nanowires.SOLUTION: A magnetic nanowire memory 1 includes: at least one magnetic nanowire 10 in which a magnetic material thin film is formed in a nanowire-shape and which includes a first recording area 11 and a second recording area 12 adjacent to each other in a longitudinal direction; and a reproduction element 30 provided for each magnetic nanowire in the film thickness direction of the magnetic nanowire, the reproduction element detecting data recorded in the magnetic nanowire 10. The reproduction element 30 includes: a magnetic field sensor 40 comprising a multilayer film in which at least three layers of a magnetization fixed layer 3, a magnetization free layer 7 and an intermediate layer 5 are laminated; and a magnetic flux guide 50 made of a magnetic shielding material and having one end disposed on a side of the first recording area 11 and the other end disposed on a side of the second recording area 12, the magnetic flux guide being disposed to sandwich the magnetic field sensor 40 between the one end and the other end in a lamination direction of the multilayer film. A direction perpendicular to a multilayer film interface of the magnetic field sensor 40 and a direction of the film thickness of the magnetic nanowire 10 are the same.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a magnetic nanowire memory that records information in binary form corresponding to the magnetization direction of magnetic domains on a magnetic recording medium made of a nanowire-shaped magnetic material, and in particular to a magnetic nanowire memory equipped with a reproducing element that reproduces the recorded information. [Background technology]

[0002] For example, broadcasting stations are hoping for the arrival of a medium capable of storing large volumes of stereoscopic video information at ultra-high speed. Future so-called three-dimensional televisions, such as spatial image reproduction televisions, will require ultra-high speed, large capacity storage. In order to realize such ultra-high speed, large capacity storage, technological development of magnetic nanowire memory is currently underway. Magnetic nanowire memory uses magnetic nanowires as a recording medium. Video information is generally sequential data, and magnetic nanowire memory employs a sequential access solid-state memory configuration (racetrack memory) that is suitable for storing data sequentially (continuously) in the length direction of the magnetic nanowire (see Patent Documents 1 to 3).

[0003] The magnetic nano-wire memories described in Patent Documents 1 to 3 use a current magnetic field generated by applying a current to a recording system to form magnetic domains (information units) magnetized upward or downward in the magnetic nano-wire, and store two values ​​corresponding to the magnetization direction. After forming (recording) the magnetic domains, the magnetic nano-wire memory shifts the formed magnetic domains by one bit in the longitudinal direction in the magnetic nano-wire by the domain wall current driving phenomenon. The magnetic nano-wire memory is configured to sequentially store binary information strings in the magnetic nano-wire by sequentially repeating the recording and driving of the magnetic domains.

[0004] For example, the memory configuration described in Patent Document 2 has a structure in which one recording element is arranged perpendicular to a large number of parallel-arranged magnetic fine-wire media, and a magnetic domain of any magnetization direction is recorded on the magnetic fine-wire media by using a current magnetic field generated by a pulse current passed through the recording element. Here, the recording element is a linear conductor wiring, and is an element for generating a magnetic field to record information on the magnetic fine-wire media, and its function corresponds to, for example, a recording head (write head) on a magnetic disk. Also, the magnetic fine wire, which is an information recording medium, has a configuration corresponding to a data track on a hard disk. Therefore, in order to detect the magnetization direction of the magnetic domain accumulated inside the magnetic fine wire, it is possible to apply something similar to an existing reproducing head for a hard disk. The reproducing head for a hard disk includes a magnetic field sensor and a magnetic flux guide (magnetic shield). The magnetic field sensor is composed of a CIP-GMR (Current In Plane Giant MagnetoResistance), CPP-GMR (Current Perpendicular to the Plane Giant MagnetoResistance), or TMR (Tunnel MagnetoResistance) element of existing technology. The magnetic flux guide supplies leakage magnetic flux from the data tracks of the hard disk medium to the magnetic field sensor. In a hard disk, the read head and the write head are integrally formed in a part called a slider, and are supplied as separate parts from the hard disk medium. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5400731 [Patent Document 2] JP 2020-27802 A [Patent Document 3] Patent Publication No. 2021-26788 Summary of the Invention [Problem to be solved by the invention]

[0006] When applying a reproducing head for a hard disk to a magnetic nano-wire memory, the following concerns arise. The magnetic nano-wire memory in this case will be described with reference to FIG. 10. In FIG. 10(a) and FIG. 10(b), the length direction of the magnetic nano-wire 310 is the x-axis, the width direction of the magnetic nano-wire 310 is the y-axis, and the thickness direction of the magnetic nano-wire 310 is the z-axis. The xy plane is a plane parallel to a wafer (not shown) on which the magnetic nano-wire material is deposited. FIG. 10(b) is a schematic diagram showing a manufacturing process of a magnetic field sensor 340 indicated by a dashed line in FIG. 10(a).

[0007] A magnetic nanowire memory 301 shown in Fig. 10(a) includes a magnetic nanowire 310 and a reproducing head 330 for a hard disk. The reproducing head 330 transmits leakage magnetic flux F generated by a magnetic domain on the magnetic nanowire 310 to a magnetic field sensor 340 through a magnetic flux guide 350 in the reproducing head 330, and detects the direction of the transmitted magnetic flux as the magnetization direction in adjacent regions 311 and 312 in the magnetic nanowire 310. The direction of the leakage magnetic flux F shown in Fig. 10(a) corresponds to the case where a downward magnetic domain is held in the region 311 of the magnetic nanowire 310 and an upward magnetic domain is held in the region 312.

[0008] On the other hand, the magnetic field sensor 340 is composed of a multilayer film formed by stacking films with a thickness of several nm or less. As shown on the left of FIG. 10(b), this multilayer film is composed of at least three layers including a magnetization fixed layer 3, an intermediate layer 5, and a magnetization free layer 7, and is fabricated by sequentially stacking them in the vertical direction of a substrate (not shown) by a sputtering method or the like. At this time, the magnetic shield 351 on the lower side (substrate side), the magnetic field sensor 340 deposited thereon, and the magnetic shield 352 on the upper side deposited thereon are manufactured as an integrated unit. Considering that the reproducing head 330 having such a structure is formed above the magnetic nanowire 310, the reproducing head 330 will be rotated by 90 degrees. 10(a) and 10(b), the interfaces of the magnetization free layer 7, the intermediate layer 5, and the magnetization fixed layer 3 in the magnetic field sensor 340 are arranged vertically (z direction) when viewed in the xz plane, and the longitudinal direction of the magnetic nanowire 310 is arranged horizontally (x direction). Therefore, the multilayer film interface (z direction) is perpendicular to the longitudinal direction (x direction) of the magnetic nanowire 310.

[0009] It is difficult to manufacture an extremely thin multilayer film by using existing technology so that the interface of the multilayer film of the magnetic field sensor 340 is arranged vertically (z direction) as shown in FIG. 10(a). Therefore, it is necessary to manufacture the reproducing head 330 by depositing each material on a wafer separate from the wafer on which the magnetic nanowire material is deposited, and then to bond the reproducing head 330 to an appropriate position on the magnetic nanowire 310. However, the width of the magnetic nanowire 310 is about 100 nm, and it is very difficult to precisely install and fix the reproducing head 330 manufactured on a separate wafer to the magnetic nanowire 310, and there is a concern that it may have a negative effect on the yield. Therefore, in order to realize the ultra-high speed and large capacity storage required for future 3D televisions, it is not sufficient to simply apply a reproducing head for a hard disk to the magnetic nanowire memory, and there is room for improvement.

[0010] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a magnetic nanowire memory having a reproducing element suitable for reproducing binary information stored in a magnetic nanowire. [Means for solving the problem]

[0011] In order to solve the above problem, the magnetic nanowire memory of the present invention comprises at least one magnetic nanowire formed in a nanowire shape from a thin film of a magnetic material and having a first recording area and a second recording area adjacent to each other in the longitudinal direction, and a reproducing element provided for each magnetic nanowire in the film thickness direction of the magnetic nanowire and detecting data recorded in the magnetic nanowire, wherein the reproducing element comprises a magnetic field sensor consisting of a multilayer film in which at least three layers are stacked, including a magnetization fixed layer, a magnetization free layer, and an intermediate layer arranged between the magnetization free layer and the magnetization fixed layer, and a magnetic flux guide made of a magnetic shielding material, one end of which is arranged on the side of the first recording area and the other end of which is arranged on the side of the second recording area, and which is arranged between the one end and the other end so as to sandwich the magnetic field sensor in the stacking direction of the multilayer film, and the direction perpendicular to the surface of the multilayer film interface of the magnetic field sensor is the same as the film thickness direction of the magnetic nanowire.

[0012] According to this configuration, the magnetic nanowire memory includes a reproducing element in the film thickness direction of the magnetic nanowire. The reproducing element has a magnetic field sensor and a magnetic flux guide. The magnetic flux guide guides leakage magnetic flux from magnetic domains recorded in the magnetic nanowire so that it passes through the magnetic field sensor. The reproducing element detects data recorded in the magnetic nanowire by the magnetic flux passing through the magnetic field sensor. In addition, the perpendicular direction of the multilayer film interface of the magnetic field sensor arranged between one end and the other end of the magnetic flux guide is the same as the film thickness direction of the magnetic nanowire. Therefore, it is possible to deposit the magnetic nanowire, the magnetic flux guide, and the magnetic field sensor on the same wafer. Effect of the Invention

[0013] The present invention provides the following excellent effects. The magnetic nanowire memory according to the present invention has a structure that allows the reproducing element to be formed integrally with the magnetic nanowire on a wafer. Therefore, it is possible to omit the procedure of precisely bonding the reproducing element, which is manufactured on a wafer other than the wafer on which the magnetic nanowire is formed, to the magnetic nanowire, thereby contributing to improving the manufacturing yield of the magnetic nanowire memory. In addition, a magnetic nanowire memory in which the magnetic nanowire, the reproducing element, and the recording element are integrally formed can be manufactured on the same wafer. According to the present invention, it is possible to provide a magnetic nanowire memory having a reproducing element suitable for reproducing binary information stored in a magnetic nanowire. In particular, it is possible to provide a reproducing element suitable for a magnetic nanowire memory capable of ultra-high speed recording and reproducing and stably retaining information for a long period of time. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic diagram showing a configuration of a magnetic nanowire memory according to an embodiment of the present invention; [Diagram 2] 1 is a schematic diagram showing the overall configuration of a magnetic nanowire memory including a recording system, a reproducing system, and a control system. [Diagram 3] FIG. 13 is a schematic diagram showing another configuration example of a reproducing element in a magnetic nanowire memory. [Figure 4] 1A to 1C are schematic diagrams showing a manufacturing method of a three-value output magnetic field sensor. [Diagram 5] FIG. 1 is an explanatory diagram of a three-value output magnetic field sensor. [Figure 6] 1 is a schematic diagram showing magnetic domains stored in a magnetic nanowire memory and an example of driving the same; [Figure 7] 4 is a schematic diagram showing the relationship between the resistance and the magnetization direction of a three-value output magnetic field sensor. FIG. [Figure 8] FIG. 1 is an explanatory diagram of a decoding method for a magnetic nanowire memory using a three-value output magnetic field sensor. [Figure 9] FIG. 13 is a schematic diagram showing a configuration of a magnetic nanowire memory according to a modified example. [Figure 10] FIG. 11 is a schematic diagram showing a configuration of a magnetic nanowire memory according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (First embodiment) The configuration of the magnetic nanowire memory according to the first embodiment of the present invention will be described with reference to Figs. 1 and 2. Fig. 1 corresponds to an enlarged view of the right end of the magnetic nanowire 10 in Fig. 2. In Fig. 1, the length direction of the magnetic nanowire 10 is the x-axis, the width direction of the magnetic nanowire 10 is the y-axis, and the thickness direction of the magnetic nanowire 10 is the z-axis. The xy plane is a plane parallel to a wafer not shown. When viewed from the zx plane, the magnetic nanowire 10 extends in the horizontal direction (x-direction), and the reproducing element 30 is disposed in the vertical direction (z-direction) relative to the magnetic nanowire 10. Note that the sizes and positional relationships of the members shown in each drawing may be exaggerated for clarity of explanation.

[0016] [Outline of the regeneration system for magnetic nanowire memory] The magnetic nano-wire memory 1 includes at least one magnetic nano-wire 10 and a reproducing element 30. The magnetic nano-wire 10 is formed by forming a thin film of a magnetic material into a thin wire shape, and has a first recording region 11 and a second recording region 12 adjacent to each other in the longitudinal direction (x direction) as shown in Fig. 1. The reproducing element 30 is provided for each magnetic nano-wire 10 in the film thickness direction (z direction) of the magnetic nano-wire 10, and detects data recorded in the magnetic nano-wire 10.

[0017] As shown in FIG. 1, the reproducing element 30 has a magnetic field sensor 40 and a magnetic flux guide 50. The magnetic field sensor 40 is made of a multilayer film in which at least three layers, a magnetization fixed layer 3, a magnetization free layer 7, and an intermediate layer 5 arranged between the magnetization fixed layer 3 and the magnetization free layer 7, are stacked. The magnetic flux guide 50 is made of a magnetic shielding material, and one end is arranged on the side of the first recording area 11, and the other end is arranged on the side of the second recording area 12, and is arranged so as to sandwich the magnetic field sensor 40 between the one end and the other end (hereinafter referred to as the center side) in the stacking direction of the multilayer film. The surface perpendicular direction (z direction) of the multilayer film interface of the magnetic field sensor 40 arranged on the center side of the magnetic flux guide 50 is the same as the film thickness direction (z direction) of the magnetic nanowire 10.

[0018] [Overall structure of magnetic nanowire memory] Next, the overall configuration of the magnetic nanowire memory, particularly the configuration of the recording system and the control system, will be described with reference to Fig. 2. The magnetic nanowire memory 1 shown in Fig. 2 has a configuration generally similar to the memory configuration described in Patent Document 2. That is, the magnetic nanowire memory 1 has a plurality of magnetic nanowires 10, a recording element 20 arranged perpendicular to the plurality of magnetic nanowires 10 and writing data to the magnetic nanowires 10 by a current magnetic field generated by supplying a write current (current A), and a plurality of reproducing elements 30 provided for each magnetic nanowire 10 and detecting the data written to the magnetic nanowire 10. Here, the magnetic nanowire memory 1 also has an integrated control unit 110, a pulse current source 120, a recording system control unit 130, and a reproducing system control unit 140.

[0019] The multiple magnetic nanowires 10 each function as a recording medium (magnetic nanowire medium) and are arranged in parallel in a plane on a substrate (not shown). The substrate is a base for constructing the magnetic nanowire memory 1 and is a substrate in the broad sense for forming the magnetic nanowires 10, the recording element 20, and the reproducing element 30, and any known substrate material can be used.

[0020] In the example shown in FIG. 2, the magnetic nanowire memory 1 includes, as an example, four magnetic nanowires 10, but the number of the magnetic nanowires 10 is not particularly limited. In the magnetic nanowire 10, a magnetic domain D of a recording bit length is formed by the recording element 20. In Fig. 2, information "1" recorded in the magnetic nanowire 10 is illustrated as a downward magnetic domain, and information "0" is illustrated as an upward magnetic domain.

[0021] The magnetic nanowire 10 can be made of known magnetic materials. Specific examples of such magnetic materials include Co / Ni multilayer films in which transition metals such as Fe, Co, Ni, Gd, and Tb and precious metals such as Pd and Pt are repeatedly laminated, multilayer films such as Co / Pt multilayer films and Tb / Co multilayer films, alloys of rare earth metals and transition metals such as Tb-Fe-Co and Gd-Fe (RE-TM alloys), L 10 The magnetic nanowire 10 may be configured by bonding a topological insulator thin film to any of these magnetic materials.

[0022] In order to drive the domain wall formed in the magnetic nanowire 10, conductor wiring 15 is connected to both ends of the magnetic nanowire 10, and a direct current pulse current (hereinafter, driving current: e in FIG. 2) is supplied from a pulse current source 120 via the conductor wiring 15. - ) is supplied. The region enclosed between a pair of nearest magnetic domain walls is called a magnetic domain, and driving (moving) a magnetic domain wall by a current is also called driving the magnetic domain. The direction in which the magnetic domain formed in the magnetic nanowire 10 is driven (magnetic domain driving direction) is one direction from the recording element 20 to the reproducing element 30. Here, the left side of the magnetic nanowire 10 in FIG. 2 is the upstream side in the magnetic domain driving direction, and the right side of the magnetic nanowire 10 is the downstream side in the magnetic domain driving direction. In addition, the positive direction of the x-axis in FIG. 1 is the magnetic domain driving direction. That is, FIG. 1 is a schematic diagram showing the vicinity of the downstream end of the magnetic nanowire 10 in the magnetic domain driving direction.

[0023] The recording element 20 is provided to record information on the magnetic nanowire 10, and is a component equivalent to a recording head in a magnetic disk, for example. The recording element 20 is a conductor perpendicular to the magnetic nanowire 10, and generates a magnetic field when a current is supplied to the recording element 20. The recording element 20 is made of a metal thin film, and is made of a general metal material for electrodes, such as metals such as Cu, Al, Au, Ag, Ta, and Cr, or alloys or multilayer films thereof. Among such metal materials, Au, which has particularly high electrical conductivity and is chemically stable, is preferable.

[0024] An interlayer insulating layer (not shown) is formed between the recording element 20 and the magnetic nanowire 10. For the interlayer insulating layer, for example, an oxide film such as SiO2 or Al2O3 or a known inorganic insulating material such as Si3N4 or MgF2 can be used. Alternatively, a laminated film of an oxide film or an inorganic insulating material may be used. In FIG. 2, the recording element 20 is disposed below the magnetic nanowire 10 (on the substrate side), but the recording element 20 may be disposed above the magnetic nanowire 10.

[0025] The method by which the recording element 20 records magnetic domains in the magnetic nanowire 10 is to supply a recording current to the recording element 20 from a pulse current source (hereinafter referred to as a recording power supply) provided externally to supply a recording current, generate a magnetic field by the current flowing through the recording element 20, and locally reverse the magnetization of the magnetic nanowire 10 by this current magnetic field. This area where the magnetization is locally reversed is recorded as a magnetic domain.

[0026] The general control unit 110 has a circuit that controls the entire data recording process and reproducing process. The general control unit 110 is a main control unit that controls all operations of the magnetic nanowire memory 1. The magnetic nanowire memory 1 performs each operation of recording (writing information), reproducing (reading information), and driving (bit shift of magnetic domains). In other words, the general control unit 110 controls the operations of the recording system control unit 130, the reproducing system control unit 140, and the pulse current source 120, and also controls input / output necessary for memory operation. The general control unit 110 controls, for example, the timing of supplying a pulse current from the pulse current source 120 to each magnetic nanowire 10. The general control unit 110 can accept an instruction to start a recording operation or an instruction to start a reproducing operation by inputting a command from the outside. An operator of the magnetic nanowire memory 1 inputs a command by operating an input device (not shown). For example, a button switch, a touch panel, a remote control, a mouse, a keyboard, etc. can be used as the input device.

[0027] The pulse current source 120 supplies a DC pulse current to each magnetic wire 10 in order to bit-shift the magnetic domain (information) formed in the magnetic wire 10. Bit shifting means shifting the magnetic domain formed in the magnetic wire 10 by approximately the recording bit length in the longitudinal direction of the magnetic wire 10 with one pulse of the pulse current.

[0028] The recording system control unit 130 has a circuit for controlling a recording current flowing through the recording element 20. The recording system control unit 130 divides the input information signal and supplies a current to the recording element 20 in order to record the divided unit information in each magnetic nanowire 10. The recording system control unit 130 may be provided with a recording power source.

[0029] The reproduction system control unit 140 has a circuit for controlling the decoding and reproduction of data detected by the reproduction elements 30. The reproduction system control unit 140 combines the information signals obtained by each reproduction element 30 to restore the signal. The restored signals (video signal, audio signal) are output from an output device (not shown). As the output device, for example, a liquid crystal display, a speaker, etc. can be used.

[0030] [Details of the read element of magnetic nanowire memory] The reproducing element 30 will be described in detail below with reference to FIG. 1 (and also with reference to FIG. 2 as appropriate). The reproducing element 30 detects the magnetization direction of the magnetic domain (information) stored in the magnetic nanowire 10. The reproducing element 30 detects the direction of leakage magnetic flux generated from the magnetic domain directly below, and outputs a signal corresponding to the magnetization direction to the reproducing system control unit 140. The reproducing element 30 is provided across the first recording area 11 and the second recording area 12 of the magnetic nanowire 10.

[0031] The first recording area 11 is disposed downstream (before) the second recording area 12 in the magnetic domain driving direction. The longitudinal lengths of the first recording area 11 and the second recording area 12 are, for example, equal to each other and are the recording bit length. In the magnetic nanowire memory 1, the magnetic domain recorded prior to the second recording area 12 is held in the first recording area 11 by the driving (bit shift of the magnetic domain) operation. Also, the magnetic domain recorded next to the first recording area 11 is held in the second recording area 12. Therefore, hereinafter, the magnetic domain held in the first recording area 11 at a certain moment is referred to as the preceding magnetic domain, and the magnetic domain held in the second recording area 12 at the same moment is referred to as the following magnetic domain.

[0032] The magnetic field sensor 40 has the same configuration as the magnetic field sensor 340 described with reference to FIG. 10. That is, the magnetic field sensor 40 is composed of a CIP-GMR, CPP-GMR or TMR element of existing technology. The magnetic field sensor 40 has a structure of at least three layers: a magnetization fixed layer 3, an intermediate layer 5, and a magnetization free layer 7. The intermediate layer 5 is disposed between the magnetization fixed layer 3 and the magnetization free layer 7. In the case of a GMR element, the intermediate layer 5 is formed of a metal thin film, and in the case of a TMR element, the intermediate layer 5 is formed of an insulating thin film.

[0033] The magnetization fixed layer 3 has a constant magnetization direction regardless of the magnetic field applied from the outside. On the other hand, the magnetization free layer 7 rotates its magnetization direction so as to follow the direction of the magnetic field applied from the outside. When the magnetization directions of the magnetization fixed layer 3 and the magnetization free layer 7 are parallel, the resistance of the magnetic field sensor 40 is small, and when the magnetization directions of the magnetization fixed layer 3 and the magnetization free layer 7 are antiparallel, the resistance of the magnetic field sensor 40 is large. Therefore, an external circuit (e.g., the reproducing system control unit 140) of the magnetic field sensor 40 can detect the resistance change of the magnetic field sensor 40 to detect the magnetization direction as a binary value, whether it is parallel or antiparallel.

[0034] In the magnetic field sensor 40, in order to uniquely determine the magnetization direction of the magnetization pinned layer 3, the magnetization pinned layer 3, the intermediate layer 5, and the magnetization free layer 7 are usually formed in this order by sputtering while applying a unidirectional magnetic field from the outside. Alternatively, a spin valve configuration may be used in which an antiferromagnetic thin film is joined to the interface opposite to the interface of the magnetization pinned layer 3 that contacts the intermediate layer 5, and the magnetization direction of the magnetization pinned layer 3 is uniquely determined by the generated exchange bias magnetic field. In this case, known materials such as Ir-Mn alloy, Pt-Mn alloy, Fe-Mn alloy, NiO insulator, and Mn3Sn topological antiferromagnetic alloy can be used as the antiferromagnetic thin film material. In addition, a protective layer can be formed on the magnetization free layer 7, or an underlayer can be formed on the magnetization pinned layer 3.

[0035] The magnetization pinned layer 3, intermediate layer 5, and magnetization free layer 7 constituting the CIP-GMR, CPP-GMR, or TMR element do not necessarily need to be deposited in this order, and may be formed continuously in this order by inverting the magnetization free layer 7, intermediate layer 5, and magnetization pinned layer 3. The magnetic field sensor 40 also includes electrodes for extracting a reproduction signal, but these are omitted from FIG.

[0036] The magnetic flux guide 50 is provided to efficiently apply leakage magnetic flux generated from magnetic domains accumulated in the magnetic nanowire 10 to the magnetic field sensor 40 . The magnetic flux guide 50 includes a front shield (first shield portion) 51, a rear shield (second shield portion) 52, and a side shield (relay shield portion) 53. The front shield 51 extends from the first recording region 11 in the width direction (y direction) of the magnetic wire 10. The rear shield 52 extends from the second recording region 12 in the width direction of the magnetic wire 10. The lateral shield 53 connects the magnetic field sensor 40, which is stacked on one of the front shield 51 and the rear shield 52, to the other of the front shield 51 and the rear shield 52.

[0037] In the embodiment shown in FIG. 1(a), the front shield 51 extends from directly above the first recording area 11 to the side of the magnetic wire 10 (positive direction of the y-axis). The rear shield 52 extends from directly above the second recording area 12 to the side of the magnetic wire 10, similar to the front shield 51. The thickness (length in the z-direction) of the front shield 51 is slightly smaller than the thickness (length in the z-direction) of the rear shield 52 by the film thickness (length in the z-direction) of the magnetic field sensor 40. As a result, the side shield 53 connects the magnetic field sensor 40 stacked on the front shield 51 to the rear shield 52.

[0038] In addition, contrary to the configuration shown in FIG. 1(a), the thickness of the front shield 51 may be made slightly thicker than the thickness of the rear shield 52, and the side shield 53 may connect the magnetic field sensor 40 stacked on the rear shield 52 to the front shield 51. In addition, in FIG. 1, the front shield 51, rear shield 52, and side shield 53 are shown as being generally rectangular parallelepipeds, as an example, but the shape of each magnetic shield is not limited to this.

[0039] The magnetic flux guide 50 is configured such that the front shield 51 takes in leakage flux from the preceding magnetic domain, and the rear shield 52 takes in leakage flux from the next magnetic domain, and the front shield 51 and rear shield 52 guide the leakage flux in a lateral direction (y direction) perpendicular to the magnetic nanowire 10. In order to detect the magnetization direction with high sensitivity, it is preferable that the length (y direction length) of the front shield 51 and rear shield 52 of the magnetic flux guide 50 be as short as possible.

[0040] The reproducing element 30 can make the surface perpendicular direction of the multilayer film interface of the magnetic field sensor 40 arranged closer to the center than one end of the magnetic flux guide 50 the same as the film deposition direction (z direction). Therefore, in manufacturing the magnetic nanowire memory 1, it is not necessary to bond the reproducing element to the magnetic nanowire as a separate component, and it becomes possible to process-form the reproducing element 30 on the same wafer on which the magnetic nanowire 10 is deposited.

[0041] Second embodiment The configuration of a magnetic fine wire memory according to a second embodiment of the present invention will be described with reference to Fig. 3. In the magnetic fine wire memory 1B shown in Fig. 3, the structure of a reproducing element 30B differs from that of the reproducing element 30 of the magnetic fine wire memory 1 shown in Fig. 1. Note that the same components as those in the magnetic fine wire memory 1 shown in Fig. 1 are denoted by the same reference numerals and will not be described.

[0042] The reproducing element 30B includes a magnetic flux guide 50B that allows the magnetic field sensor 40 to be placed directly above the magnetic nanowire 10. The magnetic flux guide 50B includes a front shield (first shield portion) 51B, a rear shield (second shield portion) 52B, and an upper shield (relay shield portion) 53B. The front shield 51B extends from the first recording region 11 in the film thickness direction (z direction) of the magnetic wire 10. The rear shield 52B extends from the second recording region 12 in the film thickness direction of the magnetic wire 10. The top shield 53B connects the magnetic field sensor 40 stacked on one of the front shield 51B and the rear shield 52B to the other of the front shield 51B and the rear shield 52B.

[0043] In FIG. 3, as an example, the front shield 51B extends from directly above the first recording area 11 to above the magnetic wire 10 (positive direction of the z-axis). The rear shield 52B extends from directly above the second recording area 12 to above the magnetic wire 10, similar to the front shield 51B. The thickness (length in the z-direction) of the front shield 51B is slightly smaller than the thickness (length in the z-direction) of the rear shield 52B by the film thickness (length in the z-direction) of the magnetic field sensor 40. As a result, the upper shield 53B connects the magnetic field sensor 40 laminated on the front shield 51B to the rear shield 52B. Conversely, the thickness of the front shield 51B may be made slightly larger than the thickness of the rear shield 52B, and the upper shield 53B may connect the magnetic field sensor 40 laminated on the rear shield 52B to the front shield 51B.

[0044] The magnetic flux guide 50B is configured such that the front shield 51B takes in leakage flux from the preceding magnetic domain, and the rear shield 52B takes in leakage flux from the next magnetic domain, and the front shield 51B and rear shield 52B each guide the leakage flux above (z direction) the magnetic nanowire 10. Also, in this embodiment, in order to detect the magnetization direction with high sensitivity, it is preferable to make the length (z direction length) of the front shield 51B and rear shield 52B of the magnetic flux guide 50B as short as possible.

[0045] The reproducing element 30B can make the surface perpendicular direction of the multilayer film interface of the magnetic field sensor 40 arranged at the center side of the magnetic flux guide 50B the same as the film deposition direction (z direction). Therefore, in manufacturing the magnetic fine-wire memory 1B, it is not necessary to bond the reproducing element to the magnetic fine wire as a separate part, and it is possible to process-form the reproducing element 30B on the same wafer on which the magnetic fine wire 10 is deposited. Furthermore, since the reproducing element 30B is formed on the upper part of the magnetic fine wire 10 in the magnetic fine-wire memory 1B, it is possible to reduce the interval between the multiple magnetic fine wires 10 arranged in the width direction (y direction) of the magnetic fine wire 10. Therefore, the magnetic fine-wire memory 1B has an advantage that the integration degree (recording surface density) of the magnetic fine wire can be improved compared to the magnetic fine-wire memory 1 having the reproducing element 30 shown in FIG. 1.

[0046] Third embodiment The reproducing element 30, 30B of the magnetic nanowire memory 1, 1B in each of the above-mentioned embodiments has been described as including a binary output magnetic field sensor 40 that detects the magnetization direction of the magnetization fixed layer 3 and the magnetization free layer 7 in binary terms, whether the magnetization directions are parallel or antiparallel, but it may also include a ternary output magnetic field sensor. A method for manufacturing a ternary output magnetic field sensor will be described with reference to Fig. 4.

[0047] First, in the first step, when the magnetization fixed layer 3 is formed, an external magnetic field H pin is applied in one direction. Here, the external magnetic field H pin It is assumed that the external magnetic field H is applied to the right direction in FIG. pin The magnetic anisotropy M pin This allows the magnetization fixed layer 3 to firmly maintain its magnetization direction.

[0048] Next, in a second step, as shown in FIG. 4(b), the intermediate layer 5 is formed on the magnetization fixed layer 3 by sputter deposition. Furthermore, in the third step, as shown in FIG. 4(c), the magnetization free layer 7 is deposited on the intermediate layer 5. At that time, the magnetic anisotropy M pin In the direction perpendicular to the external magnetic field H free Here, the external magnetic field H free It is assumed that the external magnetic field H free The magnetic anisotropy M free Therefore, the magnetic anisotropy M of the magnetization free layer 7 can be free is the magnetic anisotropy M pin can be introduced in a direction perpendicular to the

[0049] As shown in FIG. 4(c), the magnetization fixed layer 3 of the magnetic field sensor 40C has magnetic anisotropy M in the positive direction of the x-axis (first direction in the plane). pin The magnetization free layer 7 has a magnetic anisotropy M in the positive direction of the y axis (a second direction perpendicular to the first direction in the plane). free It has. According to this magnetic field sensor 40C, the magnetization direction of the magnetization free layer 7 can be in three states: parallel, perpendicular, and anti-parallel to the magnetization direction of the magnetization fixed layer 3. Therefore, the output of the magnetic field sensor 40C can realize three values: small resistance, medium resistance, and large resistance.

[0050] In detail, when no external magnetic field is applied to the magnetic field sensor 40C, the relative magnetization angle (degrees) between the magnetization fixed layer 3 and the magnetization free layer 7 is 90 degrees (see FIG. 5(b)). When the relative magnetization angle (degrees) is 90 degrees, as shown in FIG. 5(a), the resistance value of the magnetic field sensor 40C is determined by the magnetic anisotropy M introduced in the magnetization free layer 7. free This stabilizes the resistance state.

[0051] On the other hand, when an external magnetic field is applied to the magnetic field sensor 40C, the magnetization of the magnetization free layer 7 is aligned in the direction of the external magnetic field, and the resistance value changes. For example, when the magnetization directions of the magnetization fixed layer 3 and the magnetization free layer 7 become parallel due to an external magnetic field applied to the magnetic field sensor 40C, the relative magnetization angle (degrees) between the magnetization fixed layer 3 and the magnetization free layer 7 is 0 degrees, as shown in Fig. 5(b). In this case, the resistance value of the magnetic field sensor 40C becomes small, as shown in Fig. 5(a). When the magnetization directions of the magnetization fixed layer 3 and the magnetization free layer 7 become antiparallel due to an external magnetic field applied to the magnetic field sensor 40C, the relative magnetization angle (degrees) between the magnetization fixed layer 3 and the magnetization free layer 7 is 180 degrees, as shown in Fig. 5(b). In this case, the resistance value of the magnetic field sensor 40C becomes large, as shown in Fig. 5(a).

[0052] In the manufacturing method of a three-value output magnetic field sensor, the magnetization fixed layer 3, intermediate layer 5 and magnetization free layer 7 constituting the CIP-GMR, CPP-GMR or TMR element do not necessarily have to be deposited in this order, and a structure in which the magnetization free layer 7, intermediate layer 5 and magnetization fixed layer 3 are continuously formed in this order by inverting the layers. In addition, the manufacturing method of a three-value output magnetic field sensor can also include, for example, a step of forming a base layer for the magnetization fixed layer 3 before the first step, and a step of forming a protective layer on the magnetization free layer 7 after the third step. In the first step, the magnetic anisotropy M of the magnetization pinned layer 3 is set to be along the magnetic flux direction, taking into consideration the magnetic flux direction flowing in the magnetic flux guide of the completed magnetic nanowire memory. pin It is preferable to introduce

[0053] [Decoding method for magnetic nanowire memory] Next, a decoding method in the magnetic fine wire memory 1C according to the third embodiment will be described with reference to Fig. 6 (see Figs. 3, 5 and 7 as appropriate). The magnetic fine wire memory 1C shown in Fig. 6(a) differs from the magnetic fine wire memory 1B of the second embodiment in that a reproducing element 30C includes a magnetic field sensor 40C with three-value output. Note that the same components as those in the magnetic fine wire memory 1B shown in Fig. 3 are given the same reference numerals and will not be described.

[0054] As shown in Fig. 6(a), the reproducing element 30C includes a three-value output magnetic field sensor 40C and a magnetic flux guide 50B. For the sake of explanation, Fig. 6(a) shows a region of the magnetic wire 10 that is 17 times the length of the recording bit. Here, a first recording region 11 is set at the right end of the magnetic wire 10, and a second recording region 12 is set adjacent to the left of the first recording region 11. The magnetic flux guide 50B of the reproducing element 30C spans the first recording region 11 and the second recording region 12.

[0055] As an example, assume that a magnetic domain train (a train of information) is stored as shown in FIG. 6(a). Here, information "0" recorded in the magnetic nanowire 10 is illustrated as an upward magnetic domain, and information "1" is illustrated as a downward magnetic domain. For example, the second recording region 12 (magnetic domain) of the magnetic nanowire 10 is an upward magnetic domain (0 state) and is located at the beginning of the magnetic domain driving direction. The 16th magnetic domain from the beginning (the magnetic domain at the left end) is a downward magnetic domain (1 state). Note that in the initial stage, no magnetic domain is recorded in the first recording region 11 of the magnetic nanowire 10, or even if it is recorded, it will be ignored since it does not affect the explanation.

[0056] In the following text, the magnetic domain sequence will be described from left to right, from the beginning to the end of the magnetic domain drive direction. This corresponds to the reading order of the regenerative decoding described below. However, to avoid confusion with the notation of the magnetic domain sequence corresponding to the drive direction in Figure 6, in the following, the character (first) will be written near the first bit, and the character (last) will be written near the last bit, as follows: "(Beginning)0010110101110101(End)"

[0057] When a driving current is applied in the longitudinal direction of the magnetic nanowire 10, the unit bit shifts one bit at a time to the right. The three-value output magnetic field sensor 40C exhibits the following operation in accordance with the magnetization direction of the magnetic domain immediately below the front shield 51B and the magnetization direction of the magnetic domain immediately below the rear shield 52B.

[0058] <First Case> When the magnetic domain immediately below the front shield 51B is in the "zero state" and the magnetic domain immediately below the rear shield 52B is also in the "zero state", the leakage magnetic flux picked up by the front shield 51B and the rear shield 52B forms a magnetic path that repels each other, so that the effective magnetic path of the leakage magnetic flux does not pass through the magnetic field sensor 40C. Therefore, the magnetization of the magnetization free layer 7 remains in the initial state, with the magnetic anisotropy M free (see FIG. 4(c)). Therefore, the magnetic field sensor 40C outputs the resisting (M) state (see FIG. 5 and FIG. 7(b)).

[0059] <Second Case> When the magnetic domain directly below the front shield 51B is in "state 0" and the magnetic domain directly below the rear shield 52B is in "state 1", the magnetic path of the leakage magnetic flux flows counterclockwise (around the y-axis from the x-axis to the z-axis) through the front shield 51B, the magnetic field sensor 40C, and the rear shield 52B (opposite to the direction of the leakage magnetic flux F in FIG. 3(a)). As a result, the magnetization of the magnetization free layer 7 faces leftward (negative direction of the x-axis) (see FIG. 7(c)). Therefore, the magnetic field sensor 40C outputs a high resistance (H) state (see FIG. 5 and FIG. 7(c)).

[0060] <Third case> When the magnetic domain directly below the front shield 51B is in "state 1" and the magnetic domain directly below the rear shield 52B is in "state 0", the magnetic path of leakage magnetic flux flows clockwise (around the y-axis from the z-axis to the x-axis) through the rear shield 52B, the magnetic field sensor 40C, and the front shield 51B in that order (see leakage magnetic flux F in FIG. 3(a)). As a result, the magnetization of the magnetization free layer 7 faces to the right (positive direction of the x-axis) (see FIG. 7(a)). Therefore, the magnetic field sensor 40C outputs a low resistance (L) state (see FIGS. 5 and 7(a)).

[0061] <Case 4> When the magnetic domain immediately below the front shield 51B is in "state 1" and the magnetic domain immediately below the rear shield 52B is also in "state 1", similar to the first case, the leakage magnetic flux picked up by the front shield 51B and the rear shield 52B forms a magnetic path that repels each other, and the effective magnetic path of the leakage magnetic flux does not pass through the magnetic field sensor 40C. Therefore, the magnetization of the magnetization free layer 7 remains in the initial state, with the magnetic anisotropy Mfree 4C). Therefore, the magnetic field sensor 40C outputs the resisting (M) state (see FIGS. 5 and 7B).

[0062] Next, the operation of the state in which the magnetic domain of "(head) 0010110101110101 (tail)" previously stored in the magnetic nanowire 10 shown in Fig. 6(a) is shifted right by one bit at a time to the position of the reproducing element 30C by the driving current will be described with reference to Fig. 6(b) to Fig. 6(e). Note that the reproducing element 30C is not shown in Fig. 6(b) to Fig. 6(e).

[0063] Fig. 6(b) shows a schematic diagram of the magnetic domain train accumulated in the magnetic nanowire 10 after shifting right by one bit from the initial stage shown in Fig. 6(a). In this case, for the first two bits, the leading magnetic domain immediately below the front shield 51B is in "0 state" and the next magnetic domain immediately below the rear shield 52B is also in "0 state". Therefore, the ternary detection signal by the magnetic field sensor 40C is "M".

[0064] 6(c) shows a schematic diagram of the magnetic domain train stored in the magnetic nanowire 10 after a further right shift of one bit. In this case, for the first two bits, the magnetic domain immediately below the front shield 51B is in the "0 state" and the magnetic domain immediately below the rear shield 52B is in the "1 state." Therefore, the ternary detection signal by the magnetic field sensor 40C is "H."

[0065] FIG. 6(d) shows a schematic diagram of the magnetic domain sequence stored in the magnetic nanowire 10 after a further right shift of one bit. In this case, for the first two bits, the magnetic domain immediately below the front shield 51B is in the "1 state" and the magnetic domain immediately below the rear shield 52B is in the "0 state". Therefore, the ternary detection signal by the magnetic field sensor 40C becomes "L". After that, by a similar procedure, the signal sequence of "MHLHMLHLHMMLHLH" is sequentially output by the magnetic field sensor 40C from the beginning. As a result, the magnetic domain sequence (binary information of 0 and 1) stored in the magnetic nanowire memory 1C is converted (encoded) into a ternary information signal.

[0066] After a further 2-bit shift from the state shown in FIG. 6(d), the magnetic domain immediately below the front shield 51B becomes "1 state" and the magnetic domain immediately below the rear shield 52B becomes "1 state" for the first two bits, as shown in FIG. 6(e). Therefore, the ternary detection signal by the magnetic field sensor 40C becomes "M". As described below, since the signal detected in the state shown in FIG. 6(e) and the signal detected in the state shown in FIG. 6(b) are both "M", it is preferable that the recording side and the decoding side determine in advance which state the ternary detection signal "M" corresponds to.

[0067] Next, conversion (encoding) of a magnetic domain sequence (binary information of 0, 1) into a signal of ternary information and decoding into binary information will be described with reference to FIG. 8 is a schematic diagram showing the correspondence between the magnetic domain sequence of "(head) 0010110101110101 (tail)" stored in advance in the magnetic nanowire 10 and the ternary detection signal by the magnetic field sensor 40C. Note that the magnetic domain sequence 251 in FIG. 8 is arranged in accordance with the reading order for reproduction and decoding, and is arranged in the opposite order to the magnetic domain sequence in FIG. 6.

[0068] A signal sequence 252 indicated by "MHLHMLHLHMMLHLH" from the leading side (left in FIG. 8) indicates a sequence of ternary detection signals sequentially output from the magnetic field sensor 40C based on the regularity described with reference to FIGS. 6(b) to 6(e), respectively. Note that each signal appearing sequentially from the leading side in the signal sequence 252 corresponds to a signal sequentially output from the magnetic field sensor 40C when pairs of 2 bits from the leading side in the magnetic domain sequence 251 are sequentially selected while shifting the pairs by 1 bit.

[0069] In Fig. 8, the magnetic domain sequence 253 written below the signal sequence 252 indicates the decoded result of the signal sequence 252. In the case of decoding, for example, an external circuit such as the reproduction system control unit 140 (see Fig. 2) performs inverse conversion on the ternary detection signal of the magnetic field sensor 40C as it is by corresponding it to each of the first to fourth cases described above. This makes it possible to obtain the original magnetic domain sequence of "(start) 0010110101110101 (end)", i.e., the information (signal) previously stored in the magnetic nanowire 10.

[0070] For example, the leading ternary detection signal "M" of the signal sequence 252 is converted inversely to the leading 1,2-bit magnetic domain "(leading) 00" in the magnetic domain sequence 251 in accordance with the first case. Moreover, the second ternary detection signal "H" from the beginning of the signal sequence 252 corresponds to the second case, and is inversely converted to the first two or three bits of magnetic domain "01" in the magnetic domain sequence 251. Furthermore, the third ternary detection signal "L" from the beginning of the signal sequence 252 is converted inversely to the leading 3rd and 4th bits of magnetic domain "10" in the magnetic domain sequence 251, corresponding to the third case.

[0071] Skipping one, in the case of the fifth ternary detection signal "M" from the beginning of the signal sequence 252, the first and fourth cases are considered as candidates. However, in this case, the magnetic domain is reverse-converted to the 5th and 6th bits from the beginning in the magnetic domain sequence 251 to "11" so as to include the already determined fifth magnetic domain "1". In this way, in the case of the ternary detection signal "M", it can be decoded to the magnetic domain "11" or the magnetic domain "00" based on the context of the decoding.

[0072] In addition, as shown in the example of FIG. 6(a), when the magnetic domain "00" is stored in the first two bits of the magnetic nanowire 10, the ternary detection signal at the beginning of the signal sequence 252 becomes "M" as shown in the example of FIG. 8. Alternatively, when the magnetic domain "11" is stored in the first two bits of the magnetic nanowire 10, the ternary detection signal becomes "M" as well. Therefore, when the beginning of the signal sequence 252 becomes "M", it is preferable to determine in advance between the recording side and the decoding side whether the signal corresponds to the magnetic domain "00" or the magnetic domain "11". For example, it is sufficient to determine that the magnetic domain "00" is always stored in the first two bits of the magnetic nanowire 10. Alternatively, if it is determined in advance between the recording side and the decoding side that the magnetic domain "01" or "10" is always stored in the first two bits of the magnetic nanowire 10, the ternary detection signal "M" can be decoded without any problem.

[0073] The magnetic nanowire memory 1C of the third embodiment can faithfully decode the binary information stored in the magnetic nanowire 10 by first converting (encoding) the binary information read by the reproducing element 30C into a ternary information signal by the magnetic field sensor 40C in the reproducing element 30C, and then decoding it into binary information. In addition, the magnetic nanowire memory 1C combines the magnetic flux guide 50 and the three-value output magnetic field sensor 40C in the reproducing element 30C, so that the signal can be decoded with a high S / N ratio. It is more preferable to detect the output of the magnetic field sensor 40C with a lock-in amplifier in synchronization with the pulse of the driving current, because this makes it possible to extract the signal with a high S / N ratio.

[0074] Although the magnetic nanowire memory according to each embodiment of the present invention has been described above, the gist of the present invention is not limited to these descriptions and should be broadly interpreted based on the claims. Furthermore, it goes without saying that various changes and modifications based on these descriptions are also included in the gist of the present invention. For example, in the third embodiment, a three-value output magnetic field sensor 40C is incorporated into the magnetic fine wire memory 1B of the second embodiment, but the same effect can be achieved by incorporating the three-value output magnetic field sensor 40C into the magnetic fine wire memory 1 of the first embodiment.

[0075] FIG. 1 illustrates a configuration in which the front shield 51 and the rear shield 52 constituting the magnetic flux guide 50 of the reproducing element 30 are arranged perpendicular to the magnetic nanowire 10, but the structure of the magnetic flux guide 50 is not limited to this. The front shield 51 and the rear shield 52 may extend obliquely as long as they are arranged on the same side as seen from the magnetic nanowire. The lateral shield 53 is not essential. In the xy plane view, the magnetic flux guide 50 may be deformed to have a triangular shape with one side being the first recording area 11 and the second recording area 12 of the magnetic nanowire 10 and the other sides being the front shield 51 and the rear shield 52, and the magnetic field sensor 40 may be disposed at the apex of the triangle. Furthermore, in the xy plane view, the magnetic flux guide 50 may be deformed to have a semicircular ring shape with one side being the first recording area 11 and the second recording area 12 of the magnetic nanowire 10 and the front shield 51 and the rear shield 52 as circular arcs.

[0076] In each drawing, the reproducing element 30 is illustrated above the magnetic nanowire 10, but this is not limited thereto. The reproducing element may be placed below the magnetic nanowire 10 by depositing the magnetic nanowire on a wiring substrate manufactured with the reproducing element embedded therein. In addition, in Fig. 6(a), the first recording area 11 and the second recording area 12 are provided at the right end of the magnetic nanowire 10, and the right end of the magnetic nanowire 10 is set as the reproducing element position, but this is not limited to this. As shown in Fig. 9(a), a position other than the end of the magnetic nanowire 10 may be set as the reproducing element position. In other words, it is not essential to provide the first recording area 11 of the magnetic nanowire 10 at the end of the magnetic nanowire 10.

[0077] The magnetic shield material, which is the material of the magnetic flux guides 50, 50B, may be any existing magnetic thin film with high magnetic permeability and soft magnetic properties, and may be, for example, existing materials such as permalloy alloys, supermalloy alloys, Co-based amorphous materials, or multilayer films of these materials. In this case, it is preferable to sandwich a thin insulating layer 60 between the magnetic flux guides 50, 50B and the magnetic nanowire 10, as shown in Fig. 9(b), so as to prevent effects such as shunting of the driving current that flows when driving the magnetic domain in the magnetic nanowire 10.

[0078] In addition, oxides such as Ni-Zn ferrite, which are high permeability and insulating materials, can be used as the magnetic shielding material that is the material of the magnetic flux guides 50 and 50B. In this case, it is preferable because there is no need to consider ensuring insulation between the magnetic flux guides 50 and 50B and the magnetic fine wire 10. [Explanation of symbols]

[0079] 1,1B,1C Magnetic nanowire memory 3 Magnetization fixed layer 5. Middle Tier 7 Magnetization free layer 10 Magnetic thin wire 11 First recording area 12 Second recording area 30, 30B, 30C Regenerative element 40,40C Magnetic Field Sensor 50,50B Magnetic Flux Guide 51 Front shield (first shield part) 52 Rear shield (second shield part) 53 Horizontal shield (relay shield part) 51B Front shield (first shield part) 52B Rear shield (second shield part) 53B Upper shield (relay shield part) 60 Insulating layer F leakage flux

Claims

1. At least one magnetic nanowire formed of a thin magnetic material film in the shape of a nanowire and having a first recording region and a second recording region adjacent to each other in the longitudinal direction; a reproducing element provided for each of the magnetic nanowires in a film thickness direction of the magnetic nanowire, for detecting data recorded in the magnetic nanowire; The reproducing element is a magnetic field sensor including a multilayer film in which at least three layers, a magnetization fixed layer, a magnetization free layer, and an intermediate layer disposed between the magnetization free layer and the magnetization fixed layer, are stacked; a magnetic flux guide made of a magnetic shielding material, one end of which is disposed on the side of the first recording area and the other end of which is disposed on the side of the second recording area, and which is disposed between the one end and the other end so as to sandwich the magnetic field sensor in a stacking direction of the multilayer film; The magnetic nanowire memory is characterized in that the direction perpendicular to the surface of the multilayer film interface of the magnetic field sensor is the same as the thickness direction of the magnetic nanowire.

2. The magnetic flux guide comprises: a first shield part extending from the first recording region in a width direction of the magnetic nanowire; a second shield part extending from the second recording region in a width direction of the magnetic nanowire; a relay shield section that connects the magnetic field sensor stacked on one of the first shield section and the second shield section to the other of the first shield section and the second shield section; 2. The magnetic nanowire memory according to claim 1, further comprising:

3. The magnetic flux guide comprises: a first shield part extending from the first recording region in a film thickness direction of the magnetic nanowire; a second shield portion extending from the second recording region in a film thickness direction of the magnetic nanowire; a relay shield section that connects the magnetic field sensor stacked on one of the first shield section and the second shield section to the other of the first shield section and the second shield section; 2. The magnetic nanowire memory according to claim 1, further comprising:

4. A magnetic nanowire memory as described in any one of claims 1 to 3, characterized in that the magnetization fixed layer of the magnetic field sensor has magnetic anisotropy in a first direction in the plane, and the magnetization free layer has magnetic anisotropy in a second direction perpendicular to the first direction in the plane.

5. 4. The magnetic nanowire memory according to claim 1, further comprising an insulating layer between the magnetic flux guide and the magnetic nanowire.

6. 4. The magnetic nanowire memory according to claim 1, wherein the magnetic shielding material is Ni--Zn ferrite.

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