Magnetic domain wall moving element and magnetic array

Abstract

A magnetic domain wall displacement element and a magnetic array are provided. The magnetic domain wall displacement element of the present invention includes a magnetoresistance effect portion, a first electrode, a second electrode, a third electrode, a first magnetization fixed layer, and a second magnetization fixed layer. The magnetoresistance effect portion includes a reference layer, a magnetic domain wall displacement layer, and a non-magnetic layer. The magnetic domain wall displacement layer includes a first region and a second region in which a magnetization direction is fixed, and a third region in which a magnetization direction is variable. The reference layer overlaps at least a portion of the first region and the second region when viewed from a first direction, and a length of a portion of at least one of the first region and the second region in a third direction orthogonal to the first direction and a second direction is shorter than the third region.

Description

Technical Field

[0001] This invention relates to magnetic domain wall moving elements and magnetic arrays. This application claims priority based on Japanese Patent Application No. 2021-96973, filed on June 9, 2021, the contents of which are incorporated herein by reference. Background Technology

[0002] Next-generation non-volatile memories, such as flash memory, are gaining attention as miniaturization becomes increasingly limited. For example, MRAM (Magnetoresistive Random Access Memory), ReRAM (Resistive Random Access Memory), and PCRAM (Phase Change Random Access Memory) are known as next-generation non-volatile memories.

[0003] MRAM uses the resistance change caused by the change in magnetization direction for data recording. In order to achieve large capacity recording memory, research is being conducted on miniaturizing the components that make up the memory and multi-valued recording bits of each component.

[0004] Patent Document 1 discloses a domain wall moving element that can change the resistance value by moving the domain wall, and record data in a multi-valued or digital manner. Furthermore, Patent Document 1 discloses a domain wall moving region in the data recording layer (domain wall moving layer) that allows the domain wall to move, and a magnetized fixing region for limiting the range of movement of the domain wall.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2010-219104 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] Domain wall moving elements are mostly used in an integrated manner. To improve the integration of the domain wall moving elements, it is preferable that the magnetized fixing regions at both ends of the domain wall moving layer overlap with the reference layer of the domain wall moving element. However, in such a structure, there is a current path that forms from the reference layer to the magnetized fixing region, where the domain wall can move without passing through the domain wall moving layer. When current flows in this path, the MR ratio, which is the ratio of the maximum resistance value to the minimum resistance value, decreases. With a low MR ratio, the domain wall moving element cannot ensure a sufficient range of resistance value changes when precisely controlling the domain wall position, and it is difficult to accurately detect changes in resistance value. That is, it is difficult to increase the number of bits for multi-value data recording of the domain wall moving element.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide a magnetic domain wall moving element and magnetic array with a large MR ratio that can increase the number of bits for multi-value data recording.

[0011] Means for solving technical problems

[0012] (1) The domain wall moving element of the first embodiment includes a magnetoresistive effect section, a first electrode, a second electrode, a third electrode, a first magnetization fixing layer, and a second magnetization fixing layer. The magnetoresistive effect section includes: a reference layer containing a ferromagnetic material; a domain wall moving layer containing a ferromagnetic material; and a non-magnetic layer sandwiched between the reference layer and the domain wall moving layer in a first direction. The domain wall moving layer extends in a second direction orthogonal to the first direction. The domain wall moving layer includes: a first region where the magnetization direction is fixed; a second region where the magnetization direction is fixed in a direction different from the magnetization direction of the first region; and a third region located in the second direction sandwiched between the first region and the second region, and whose magnetization direction is variable. The first electrode is electrically connected to the first region. The second electrode is electrically connected to the second region. The third electrode is electrically connected to the reference layer and is located in the first direction on the side opposite to the non-magnetic layer, with the reference layer as a reference. The first magnetization fixing layer is located between the first region and the first electrode, and is used to magnetize and fix the first region. The second magnetization fixing layer is located between the second region and the second electrode, and is used to magnetize and fix the second region. The reference layer overlaps with at least a portion of the first region and the second region when viewed from the first direction. A portion of at least one of the first region and the second region is shorter than the third region in a third direction orthogonal to the first and second directions.

[0013] (2) Alternatively, the domain wall moving element described above may further include a substrate. Alternatively, the reference layer may be closer to the substrate than the domain wall moving layer.

[0014] (3) In the magnetic domain wall moving element described above, at least one of the first region and the second region has a longer length in the second direction than in the third direction.

[0015] (4) In the domain wall moving element described above, at least one of the first region and the second region may have: a first portion longer than the third region in the third direction; and a second portion shorter than the third region in the third direction. Alternatively, the first portion may be closer to the third region in the second direction than the second portion.

[0016] (5) In the domain wall moving element described above, at least one of the first region and the second region gradually shortens in length in the third direction as it moves from the first end connected to the third region to the second end on the opposite side of the second direction.

[0017] (6) In the domain wall moving element described above, the film thickness of the end portion of the third region in the second direction is greater than the film thickness of the central portion of the third region in the second direction, and the length of the end portion in the third direction is shorter than the length of the central portion in the third direction.

[0018] (7) In the domain wall moving element described above, when viewed from the first direction, the outer periphery of the first surface of the third electrode overlaps with at least one of the first region and the second region, wherein the first surface is the surface of the third electrode closest to the reference layer.

[0019] (8) In the above-described domain wall moving element, when viewed from the first direction, the domain wall moving layer is contained within the first surface of the third electrode, wherein the first surface is the surface of the third electrode closest to the reference layer.

[0020] (9) In the domain wall moving element described above, the length of the longest portion of the first surface of the third electrode in the third direction is shorter than the length of the longest portion of the first surface in the second direction, wherein the first surface is the surface of the third electrode closest to the reference layer.

[0021] (10) In the domain wall moving element described above, the thickness of the first magnetized fixing layer is greater than the thickness of the second magnetized fixing layer, and when viewed from the first direction, the distance from the geometric center of the first surface of the third electrode to the first magnetized fixing layer is less than the distance from the geometric center of the first surface to the second magnetized fixing layer, wherein the first surface is the surface of the third electrode closest to the reference layer.

[0022] (11) In the domain wall moving element described above, when viewed from the first direction, the first region is contained within the first electrode, and the distance between the outer periphery of the first region and the outer periphery of the first electrode is shortest at the first point.

[0023] (12) The magnetic array of the second type has multiple domain wall moving elements of the above type.

[0024] Invention Effects

[0025] The magnetic domain wall moving element and magnetic array described above have a large MR ratio, which can increase the number of bits for multi-value data recording. Attached Figure Description

[0026] Figure 1 This is a structural diagram of the magnetic array according to the first embodiment.

[0027] Figure 2 This is a cross-sectional view near the domain wall moving element of the magnetic array in the first embodiment.

[0028] Figure 3 This is a cross-sectional view of the domain wall moving element of the first embodiment.

[0029] Figure 4 This is a top view of the domain wall moving element of the first embodiment.

[0030] Figure 5 This is a top view of the domain wall moving element of the second embodiment.

[0031] Figure 6 This is a top view of the domain wall moving element of the third embodiment.

[0032] Figure 7 This is a cross-sectional view of the domain wall moving element in the fourth embodiment.

[0033] Figure 8 This is a top view of the domain wall moving element of the fourth embodiment.

[0034] Figure 9 This is a top view of the domain wall moving element of the fifth embodiment.

[0035] Figure 10This is a top view of the domain wall moving element of the sixth embodiment.

[0036] Figure 11 This is a cross-sectional view of the domain wall moving element in the seventh embodiment.

[0037] Figure 12 This is a top view of the domain wall moving element of the seventh embodiment.

[0038] Figure 13 This is a top view of the domain wall moving element of the eighth embodiment.

[0039] Figure 14 This is a cross-sectional view of the magnetic domain wall moving element in Modified Example 1.

[0040] Explanation of reference numerals in the attached figures

[0041] 1…Magnetic domain wall moving layer, 2…Non-magnetic layer, 3…Reference layer, 10…Magnetic reluctance effect section, 20, 20A…First magnetization fixing layer, 30…Second magnetization fixing layer, 40, 40A, 40B, 40C, 40D…Third electrode, 40a, 40b, 40c, 40d…First surface, 41…First electrode, 42…Second electrode, 90…Insulating layer, 100, 101, 102, 103, 104, 105, 106, 107, 10 8…domain wall moving element, 200…magnetic array, A1, A1A, A1B, A1C…region 1, A1Aa…part 1, A1Ab…part 2, A2…region 2, A3, A3A…region 3, CL…second wiring, DW…domain wall, RL…third wiring, Sub…substrate, SW1…first switching element, SW2…second switching element, SW3…third switching element, w1, w2…wiring, WL…first wiring. Detailed Implementation

[0042] Hereinafter, embodiments of the present invention will be described in detail with appropriate reference to the accompanying drawings. In the following description, the drawings sometimes show enlarged portions of the features for ease of understanding, and the dimensions and proportions of the constituent elements may differ from the actual figures. The materials, dimensions, etc., illustrated in the following description are examples, and the present invention is not limited thereto; appropriate modifications can be made within the scope of achieving the effects of the present invention.

[0043] First, the directions are defined. The x-direction and y-direction are related to the substrate Sub (see below) discussed later. Figure 2The x-direction is roughly parallel to one side of the magnetic domain wall moving layer 1, which will be described later. The x-direction is an example of the second direction. The y-direction is orthogonal to the x-direction. The y-direction is an example of the third direction. The z-direction is the direction from the substrate Sub to the magnetic domain wall moving element, which will be described later. The z-direction is an example of the first direction. In this specification, the +z direction is sometimes referred to as "up" and the -z direction as "down," but these expressions are for convenience and do not specify the direction of gravity.

[0044] In addition, the following terms are defined. In this specification, "extending in the x-direction" means that the length of the structure in the x-direction is longer than its length in the y-direction and z-direction. The same applies to other directions. Furthermore, in this specification, "connection" is not limited to direct connections, but also includes indirect connections through other layers.

[0045] [First Implementation]

[0046] Figure 1 This is a structural diagram of the magnetic array 200 according to the first embodiment. The magnetic array 200 includes a plurality of domain wall moving elements 100, a plurality of first wirings WL, a plurality of second wirings CL, a plurality of third wirings RL, a plurality of first switching elements SW1, a plurality of second switching elements SW2, and a plurality of third switching elements SW3. The magnetic array 200 can be used, for example, in magnetic memories, multiply-accumulate arithmetic units, neuromorphic devices, spin memristors, and magneto-optical elements.

[0047] Each of the first wiring lines WL is a write wiring. Each of the first wiring lines WL is used to electrically connect the power supply to one or more domain wall moving elements 100. The power supply can be connected to one end of the magnetic array 200 during use.

[0048] Each of the second wiring CLs is a shared wiring. A shared wiring is a wiring that can be used for both data writing and reading. Each of the second wiring CLs is used to electrically connect a reference potential to one or more domain wall moving elements 100. The reference potential is, for example, ground. The second wiring CL can be provided for each of multiple domain wall moving elements 100 individually, or it can be provided for multiple domain wall moving elements 100.

[0049] Each of the third wirings RL is a readout wiring. Each of the third wirings RL is used to electrically connect a power supply or reference potential to one or more magnetic domain wall moving elements 100. The power supply can be connected to one end of the magnetic array 200 during use.

[0050] exist Figure 1In this configuration, multiple domain wall moving elements 100 are each connected to a first switching element SW1, a second switching element SW2, and a third switching element SW3. The first switching element SW1 is connected between each domain wall moving element 100 and a first wiring WL. The second switching element SW2 is connected between each domain wall moving element 100 and a second wiring CL. The third switching element SW3 is connected between each domain wall moving element 100 and a third wiring RL.

[0051] When the specified first switching element SW1 and second switching element SW2 are turned on, a write current flows between the first wiring WL and the second wiring CL, which are connected to the specified domain wall moving element 100. When the specified second switching element SW2 and third switching element SW3 are turned on, a read current flows between the second wiring CL and the third wiring RL, which are connected to the specified domain wall moving element 100.

[0052] The first switching element SW1, the second switching element SW2, and the third switching element SW3 are each elements that control the flow of current. The first switching element SW1, the second switching element SW2, and the third switching element SW3 are, for example, elements that utilize phase transitions of crystal layers, such as transistors and bidirectional threshold switches (OTS); elements that utilize changes in band structure, such as metal-insulator transfer (MIT) switches; elements that utilize breakdown voltage, such as Zener diodes and avalanche diodes; and elements whose conductivity changes with atomic positions.

[0053] Any of the first switching element SW1, the second switching element SW2, and the third switching element SW3 can be shared by a domain wall moving element 100 connected to the same wiring. For example, if the first switching element SW1 is shared, a first switching element SW1 is provided upstream (at one end) of the first wiring WL. For example, if the second switching element SW2 is shared, a second switching element SW2 is provided upstream (at one end) of the second wiring CL. For example, if the third switching element SW3 is shared, a third switching element SW3 is provided upstream (at one end) of the third wiring RL.

[0054] Figure 2 This is a cross-sectional view near the domain wall moving element 100 of the magnetic array 200 in the first embodiment. Figure 2 It is Figure 1 One of the domain wall moving elements 100 is obtained by truncating the cross section by the xz plane at the center of the width of the domain wall moving layer 1 in the y direction.

[0055] Figure 2The first switching element SW1 and the second switching element SW2 shown are transistors Tr. Transistor Tr has a gate electrode G, a gate insulating film GI, and a source electrode S and a drain electrode D formed on a substrate Sub. The source electrode S and the drain electrode D are defined by the direction of current flow and are both active regions. Figure 2 This is just one example; the positional relationship between the source (S) and drain (D) can be reversed. The substrate (Sub) is, for example, a semiconductor substrate. The third switching element (SW3) is electrically connected to the third wiring (RL), for example in... Figure 2 It is located at a position offset in the y-direction.

[0056] Each transistor Tr is electrically connected to the domain wall moving element 100 via wirings w1 and w2. Wirings w1 and w2 contain a conductive material. Wiring w1 is a via wiring extending in the z-direction. Wiring w2 is an in-plane wiring extending in either direction within the xy-plane. Wirings w1 and w2 are formed within openings in the insulating layer 90.

[0057] Insulating layer 90 is used to insulate between wires or components in multilayer wiring. Insulating layer 90 is, for example, silicon oxide (SiO2). x ), silicon nitride (SiN) x Silicon carbide (SiC), chromium nitride (CrN), silicon carbonitride (SiCN), silicon oxynitride (SiON), aluminum oxide (Al2O3), zirconium oxide (ZrO2) x Magnesium oxide (MgO), etc.

[0058] exist Figure 2 The image shows an example where the domain wall moving element 100 is located above the substrate Sub with the insulating layer 90 in between, but the domain wall moving element 100 can also be located on the substrate Sub.

[0059] [Magnetic domain wall moving element]

[0060] Figure 3 It is a cross-sectional view obtained by cutting the domain wall moving element 100 using the xz plane at the center of the width in the y direction of the domain wall moving layer 1. Figure 3 It is along Figure 4 The cross section of line AA. Figure 4 This is a top view obtained by looking down at the magnetic domain wall moving element 100 from the z-direction. Figure 4 In the diagram, dashed lines represent the portions of the first electrode 41, the second electrode 42, and the third electrode 40 that overlap with the magnetoresistive effect section 10. Figure 3 The arrow shown is an example of the orientation direction of magnetization in a ferromagnetic material.

[0061] The domain wall moving element 100 is, for example, a three-terminal element having a magnetoresistive effect portion 10, a first magnetization fixing layer 20, a second magnetization fixing layer 30, a first electrode 41, a second electrode 42, and a third electrode 40. The domain wall moving element 100 is surrounded by an insulating layer 90.

[0062] The magnetoresistive effect unit 10 includes a domain wall moving layer 1, a non-magnetic layer 2, and a reference layer 3. The domain wall moving element 100, for example, sequentially includes, from the side closest to the substrate Sub, a third electrode 40, a reference layer 3, a non-magnetic layer 2, a domain wall moving layer 1, a first magnetization fixing layer 20 and a second magnetization fixing layer 30, a first electrode 41, and a second electrode 42. The reference layer 3 is closer to the substrate Sub than the domain wall moving layer 1, and the domain wall moving element 100 is referred to as a bottom fixing structure. When writing data to the magnetoresistive effect unit 10, a write current flows along the domain wall moving layer 1. When reading data from the magnetoresistive effect element 10, a read current flows between the third electrode 40 and either the first electrode 41 or the second electrode 42, and a current is applied in the z-direction of the magnetoresistive effect unit 10.

[0063] The domain wall moving layer 1 extends in the x-direction. The domain wall moving layer 1 has multiple magnetic domains internally, and domain walls (DWs) are present at the boundaries of these domains. The domain wall moving layer 1 is, for example, a layer capable of magnetically recording multi-valued data through changes in magnetic state. The domain wall moving layer 1 is sometimes referred to as an analog layer or a magnetic recording layer.

[0064] The domain wall moving layer 1 has a first region A1, a second region A2, and a third region A3. The first region A1 is, for example, a region in the x-direction extending from a first end of the domain wall moving layer 1 to a position overlapping with the inner end of the first magnetization fixing layer 20. The second region A2 is, for example, a region in the x-direction extending from a second end opposite to the first end of the domain wall moving layer 1 to a position overlapping with the inner end of the second magnetization fixing layer 30. The third region A3 is a region sandwiched between the first region A1 and the second region A2 in the x-direction.

[0065] Magnetization M in region A1 of region 1 A1 For example, the magnetization M is fixed to the first magnetization fixing layer 20. 20 In the same direction. Magnetization M in region A2 of the second region. A2 For example, the magnetization M is fixed to the second magnetization fixing layer 30. 30 In the same direction. Fixed magnetization means that the magnetization will not reverse during the normal operation of the domain wall moving element 100 (without being subjected to an external force exceeding the intended range). Magnetization M of region A1. A1 and the magnetization M of region A2 A2 For example, the magnetization directions are opposite.

[0066] Region A3 is a region where the magnetization direction can change and the domain walls DW can move. Region A3 has a roughly constant length in the y-direction, for example. Within region A3, the film thickness t at the end in the x-direction, for example... E The film thickness t in the central part is greater than the x-direction. C The film thickness of region A3 increases continuously, for example, from the center in the x-direction towards the end in the x-direction. Region A3 has a first magnetic domain A3a and a second magnetic domain A3b. The magnetization M of the first magnetic domain A3a... A3a Magnetization M of the second magnetic domain A3b A3b For example, the magnetization directions are opposite. The boundary between the first magnetic domain A3a and the second magnetic domain A3b is the domain wall DW. The magnetization M of the first magnetic domain A3a A3a For example, in the magnetization M of region A1 in the first region A1 Oriented in the same direction. Magnetization M of the second magnetic domain A3b. A3b For example, in the magnetization M of region A2 in the second region A2 Oriented in the same direction. The domain wall DW moves in principle within region 3 A3 and will not intrude into region 1 A1 and region 2 A2.

[0067] like Figure 4 As shown, the length W in the y-direction of the first region A1 A1 The length W in the y-direction of region A3 of the third region A3 Short. Additionally, the length W in the y-direction of region A2 in the second region is... A2 The length W in the y-direction of region A3 of the third region A3 Short. Here, the length in the y-direction of each region refers to the average of the length in the y-direction of the lower surface of each region and the length in the y-direction of the upper surface of each region. Here, the length W is represented. A1 and length W A2 Both are longer than length W A3 A short example, but it could also be just a length W. A1 and length W A2 either of them is longer than the length W A3 Short. For example, the length of region A1 in the x-direction is longer than its length in the y-direction. Similarly, region A2 may also be longer in the x-direction than in the y-direction. The boundaries between region A1 and region A3, and between region A2 and region A3, are, for example, approximately orthogonal to the x-direction, which is the extension direction of the magnetic domain wall moving layer 1.

[0068] When the volume ratio of the first magnetic domain A3a to the second magnetic domain A3b within the third region A3 changes, the domain wall DW moves. The domain wall DW moves due to the flow of write current in the x-direction of the third region A3. For example, when a write current (e.g., a current pulse) in the +x direction is applied to the third region A3, electrons flow in the -x direction opposite to the current, thus the domain wall DW moves in the -x direction. When current flows from the first magnetic domain A3a to the second magnetic domain A3b, the spin-polarized electrons in the second magnetic domain A3b reverse the magnetization of the first magnetic domain A3a. This magnetization reversal of the first magnetic domain A3a causes the domain wall DW to move in the -x direction.

[0069] When the volume ratio of the first magnetic domain A3a to the second magnetic domain A3b in the domain wall moving layer 1 changes, the resistance value of the domain wall moving element 100 changes. The resistance value of the domain wall moving element 100 changes accordingly with the relative angle of magnetization of the ferromagnetic layer sandwiching the non-magnetic layer 2. Figure 3 In the case of the domain wall moving element 100 shown, the resistance value of the domain wall moving element 100 is related to the magnetization M of the domain wall moving layer 1. A1 M A3a M A3b M A2 The relative angle with the magnetization M3 of reference layer 3 changes accordingly. When the proportion of the first magnetic domain A3a increases, the resistance value of the domain wall moving element 100 decreases, and when the proportion of the second magnetic domain A3b increases, the resistance value of the domain wall moving element 100 increases. By precisely controlling the position of the domain wall DW, the resistance value can be precisely controlled, enabling simulated multi-value data recording.

[0070] In the domain wall moving element 100, the reference layer 3 overlaps with the first region A1 and the second region A2 across the non-magnetic layer 2. The magnetized first region A1 and the fixed second region A2 do not contribute to the change in resistance of the domain wall moving element 100. That is, when the proportion of the first region A1 and the second region A2 in the domain wall moving layer 1 increases, the ratio of the maximum resistance to the minimum resistance of the domain wall moving element 100, i.e., the MR ratio, decreases.

[0071] The domain wall moving layer 1 comprises a magnetic material. The domain wall moving layer 1 can be a ferromagnetic material, a ferrimagnetic material, or a combination thereof with an antiferromagnetic material whose magnetic state can be changed by an electric current. The domain wall moving layer 1 preferably contains at least one element selected from Co, Ni, Fe, Pt, Pd, Gd, Tb, Mn, Ge, and Ga. Examples of materials used in the domain wall moving layer 1 include multilayer films of Co and Ni, multilayer films of Co and Pt, multilayer films of Co and Pd, multilayer films of CoFe and Pd, MnGa-type materials, GdCo-type materials, and TbCo-type materials. Ferrimagnetic materials such as MnGa-type materials, GdCo-type materials, and TbCo-type materials have low saturation magnetization, requiring a low threshold current for moving the domain wall DW. Furthermore, multilayer films of Co and Ni, multilayer films of Co and Pt, and multilayer films of Co and Pd have high coercivity, resulting in a slow movement speed of the domain wall DW. Antiferromagnetic materials include, for example, Mn3X (where X is Sn, Ge, Ga, Pt, Ir, etc.), CuMnAs, Mn2Au, etc. The domain wall moving layer 1 can be composed of multiple layers. The domain wall moving layer 1 can also be made of the same material as the reference layer 3 described later.

[0072] The non-magnetic layer 2 is located between the magnetic domain wall moving layer 1 and the reference layer 3. For example, the non-magnetic layer 2 is stacked on one side of the reference layer 3.

[0073] The nonmagnetic layer 2 is made of, for example, a nonmagnetic insulator, semiconductor, or metal. Examples of nonmagnetic insulators include Al₂O₃, SiO₂, MgO, MgAl₂O₄, and materials obtained by replacing a portion of the Al, Si, and Mg in these materials with Zn, Be, etc. These materials have large band gaps and excellent insulation properties. When the nonmagnetic layer 2 is made of a nonmagnetic insulator, it serves as a tunnel barrier layer. Examples of nonmagnetic metals include Cu, Au, and Ag. Examples of nonmagnetic semiconductors include Si, Ge, CuInSe₂, CuGaSe₂, and Cu(In,Ga)Se₂.

[0074] The thickness of the non-magnetic layer 2 is, for example, The above can be used as a basis for... The above applies. When the thickness of the non-magnetic layer 2 is thick, the resistive area (RA) of the domain wall moving element 100 is large. The resistive area (RA) of the domain wall moving element 100 is preferably 1 × 10⁻⁶. 4 Ωμm 2 The above is preferred, with 5×10 being more ideal. 4 Ωμm 2 The resistive area (RA) of the domain wall moving element 100 is represented by the product of the element resistance of the domain wall moving element 100 and the element cross-sectional area of ​​the domain wall moving element 100 (the area of ​​the cross-section obtained by cutting the non-magnetic layer 2 using the xy plane).

[0075] The reference layer 3, together with the domain wall moving layer 1, sandwiches a non-magnetic layer 2. The reference layer 3 is, for example, stacked on the third electrode 40. The reference layer 3 is located at a position overlapping the domain wall moving layer 1 in the z-direction. At least a portion of the reference layer 3 is located at a position overlapping each of the first region A1, the second region A2, and the third region A3 in the z-direction. The magnetization M3 of the reference layer 3 is greater than the magnetization M of the third region A3 of the domain wall moving layer 1. A3a M A3b Difficult to reverse. The magnetization M3 of reference layer 3 is applied to region A3 by magnetization M3. A3a M A3b When the external force reverses the degree of reversal, the direction remains unchanged and is fixed. Reference layer 3 is sometimes referred to as the magnetization fixation layer. Reference layer 3 can be composed of multiple layers. For example, it can have multiple ferromagnetic layers and an intermediate layer sandwiched between multiple ferromagnetic layers. The two ferromagnetic layers sandwiching the intermediate layer can be magnetically coupled to form a synthetic antiferromagnetic structure (SAF).

[0076] Reference layer 3 contains a ferromagnetic material. Reference layer 3 may contain, for example, a material that readily exhibits a coherent tunneling effect between itself and the domain wall moving layer 1. Reference layer 3 may include, for example, a metal selected from Cr, Mn, Co, Fe, and Ni; an alloy containing one or more of these metals; or an alloy containing these metals and at least one of the elements selected from B, C, and N. Reference layer 3 may be, for example, Co-Fe, Co-Fe-B, or Ni-Fe.

[0077] Reference layer 3 could be, for example, a Heussler alloy. Heussler alloys are half-metals with high spin polarizability. They are intermetallic compounds with a chemical composition of XYZ or X2YZ, where X is a transition metal or noble metal element from the Co, Fe, Ni, or Cu group of the periodic table; Y is a transition metal from the Mn, V, Cr, or Ti group or an element of X; and Z is a typical element from Groups IIIA to VA. Examples of Heussler alloys include Co2FeSi, Co2FeGe, Co2FeGa, Co2MnSi, and Co2Mn. 1-a Fe a Al b Si 1-b Co2FeGe 1-c Ga c wait.

[0078] The first magnetization fixing layer 20 and the second magnetization fixing layer 30 are directly or indirectly connected to the domain wall moving layer 1. Indirect connection means that other layers are sandwiched between the first magnetization fixing layer 20 and the domain wall moving layer 1, and between the second magnetization fixing layer 30 and the domain wall moving layer 1. The first magnetization fixing layer 20 and the second magnetization fixing layer 30 are, for example, located on the domain wall moving layer 1. The first magnetization fixing layer 20 and the second magnetization fixing layer 30 are spaced apart in the x-direction. The first magnetization fixing layer 20 is used to magnetize M in the first region A1. A1 Fixed. The second magnetization fixing layer 30 is used to magnetize the second region A2. A2 Fixed. The first magnetized fixing layer 20 and the second magnetized fixing layer 30 are, for example, located at positions that overlap with the non-magnetic layer 2 and the reference layer 3 in the z-direction.

[0079] The first magnetization fixing layer 20 and the second magnetization fixing layer 30, for example, include ferromagnetic layers. The first magnetization fixing layer 20 and the second magnetization fixing layer 30, for example, include materials different from those of the domain wall moving layer 1, and their film structures differ from those of the domain wall moving layer 1. Furthermore, the first magnetization fixing layer 20 and the second magnetization fixing layer 30, for example, can be composed of multiple layers. For example, they can have multiple ferromagnetic layers and an intermediate layer sandwiched between the multiple ferromagnetic layers. The two ferromagnetic layers sandwiching the intermediate layer can be magnetically coupled to form a synthetic antiferromagnetic structure (SAF). Moreover, the first magnetization fixing layer 20 and the second magnetization fixing layer 30 can have different film structures and film thicknesses.

[0080] The third electrode 40 is electrically connected to the reference layer 3. The third electrode 40 is, for example, located on the substrate Sub side closer to the reference layer 3. The third electrode 40 is, for example, located on the side opposite to the non-magnetic layer 2, with the reference layer 3 as a reference. The first electrode 41 is, for example, electrically connected to the first region A1 via the first magnetized fixing layer 20. The first magnetized fixing layer 20 is located between the first region A1 and the first electrode 41. The second electrode 42 is, for example, electrically connected to the second region A2 via the second magnetized fixing layer 30. The second magnetized fixing layer 30 is located between the second region A2 and the second electrode 42. The third electrode 40, the first electrode 41, and the second electrode 42 are, for example, made of non-magnetic conductive materials, including materials with higher thermal conductivity than the magnetic domain wall moving layer 1 and the reference layer 3. Furthermore, the third electrode 40, the first electrode 41, and the second electrode 42 may, for example, be formed of different materials. The third electrode 40, the first electrode 41, and the second electrode 42 are, for example, via wiring extending in the z-direction.

[0081] The domain wall moving element 100 of the first embodiment has a large MR ratio, which enables the number of bits for multi-value data recording to increase.

[0082] In the domain wall moving element 100, as described above, to improve integration, the first region A1 and the second region A2 are located at a position overlapping the reference layer 3 in the z-direction, separated by the non-magnetic layer 2. The lengths of the first region A1 and the second region A2 in the y-direction are shorter than the length of the third region A3 in the y-direction. By forming such a structure, the proportion of the first region A1 and the second region A2, which do not contribute to the change in resistance value in the domain wall moving layer 1, can be reduced. That is, the ratio of the maximum resistance value to the minimum resistance value, i.e., the MR ratio, of the domain wall moving element 100 can be increased, thereby increasing the number of bits for multi-value data recording. In addition, the concept of forming the width of the magnetization fixing region thinner than the width of the domain wall moving region in order to increase the number of bits for multi-value data recording, as in the domain wall moving element of this embodiment, is contrary to the conventional technical common sense that the width of the magnetization fixing region is formed thicker than the width of the domain wall moving region in order to achieve the stabilization of the magnetization fixing function.

[0083] Furthermore, in the first embodiment, the lengths of the first region A1 and the second region A2 of the domain wall moving element 100 are longer in the x-direction than in the y-direction. When the lengths of the first region A1 and the second region A2 in the y-direction are shorter than the lengths of the third region A3 in the y-direction, the current density during data writing is higher in the first region A1 and the second region A2 than in the third region A3. When the current density increases, the domain wall DW moves at high speed. By making the lengths of the first region A1 and the second region A2 longer in the x-direction than in the y-direction, the proportion of the first region A1 and the second region A2 in the domain wall moving layer 1 can be reduced, and the domain wall DW is prevented from reaching the outer ends of the first region A1 and the second region A2, thus preventing the entire domain wall moving layer 1 from becoming a single domain.

[0084] Furthermore, in the domain wall moving element 100 of the first embodiment, the boundaries between the first region A1 and the third region A3, and the boundaries between the second region A2 and the third region A3, are approximately orthogonal to the x-direction, which is the extension direction of the domain wall moving layer 1. By making the boundaries between the first region A1 and the third region A3, and the boundaries between the second region A2 and the third region A3, orthogonal to the x-direction, which is the extension direction of the domain wall moving layer 1, the domain wall DW can always move in a state that is nearly parallel to the y-direction. When the domain wall DW always moves in a state that is nearly parallel to the y-direction, even when the position of the domain wall DW is precisely controlled to simulate a change in the resistance value, the amount of change in the resistance value can always be constant.

[0085] The magnetization direction of each layer of the domain wall moving element 100 can be determined, for example, by measuring the magnetization curve. The magnetization curve can be measured, for example, using MOKE (Magneto Optical Kerr Effect). The measurement using MOKE is a measurement method that uses the magneto-optical effect (magneto-Kerr effect) that causes rotation of the polarization direction by incident linearly polarized light onto the object being measured.

[0086] The domain wall moving element 100 can be fabricated using known methods. The layers of the domain wall moving element 100 are formed and processed into a predetermined shape. The deposition of each layer can be performed using sputtering, chemical vapor deposition (CVD), electron beam evaporation (EB evaporation), atomic laser deposition, etc. The processing of each layer can be performed using techniques such as photolithography and etching (e.g., Ar etching).

[0087] (Second Implementation)

[0088] Figure 5 This is a top view obtained from the z-direction, looking down at the magnetic domain wall moving element 101 of the second embodiment. Figure 5 In the figure, dashed lines indicate the portions of the first electrode 41, the second electrode 42, and the third electrode 40 that overlap with the magnetoresistive effect section 10. In the magnetic domain wall moving element 101 of the second embodiment, the structures of the first region A1, the second region A2, the first electrode 41, and the second electrode 42 differ from those of the first embodiment. In the second embodiment, the same reference numerals are used for structures identical to those in the first embodiment, and descriptions are omitted.

[0089] like Figure 5 As shown, the first region A1A has a first part A1Aa and a second part A1Ab. The length W of the first part A1Aa in the y-direction is... A1Aa The length W of region A3 in the y direction is greater than that of region A3. A3 Length. The length W of part A1Ab in the y-direction. A1Ab The length W of region A3 in the y direction is greater than that of region A3. A3 Short. The length W of part 1 A1Aa in the y-direction. A1Aa The length W of part A1Ab in the y direction is greater than that of part A1Ab in part 2. A1Ab It is longer. Part 1, A1Aa, is closer to region 3, A3, in the x-direction than part 2, A1Ab.

[0090] Furthermore, the second region A2A has a first part A2Aa and a second part A2Ab. The length W of the first part A2Aa in the y-direction is... A2Aa The length W of region A3 in the y direction is greater than that of region A3. A3 Length. The length W of part A2Ab in the y-direction. A2AbThe length W of region A3 in the y direction is greater than that of region A3. A3 Short. The length W of part 1, A2Aa, in the y-direction. A2Aa The length W of part A2Ab in the y direction is greater than that of part A2Ab in part 2. A2Ab The length is greater. Part 1, A2Aa, is closer to region 3, A3, in the x-direction than part 2, A2Ab.

[0091] The domain wall moving element 101 of the second embodiment can achieve the same effect as the domain wall moving element 100 of the first embodiment. In addition, in the first region A1A, by providing a first portion A1Aa with a length in the y-direction that is longer than that of the third region A3 on the side of the third region A3, the current density during data writing can be reduced, and the domain wall DW can be prevented from intruding into the interior of the first region A1A.

[0092] Furthermore, this example shows that region A1A and region A2A each have a first part and a second part, but it is also possible that only either region A1A or region A2A has a first part and a second part.

[0093] (Third Implementation)

[0094] Figure 6 This is a top view obtained from the z-direction, looking down at the magnetic domain wall moving element 102 of the third embodiment. Figure 6 In the figure, dashed lines indicate the portions of the first electrode 41, the second electrode 42, and the third electrode 40 that overlap with the magnetoresistive effect section 10. In the domain wall moving element 102 of the third embodiment, the structures of the first region A1 and the third region A3 differ from those of the first embodiment. In the second embodiment, the same reference numerals are used for structures identical to those in the first embodiment, and descriptions are omitted.

[0095] like Figure 6 As shown, the length of the first region A1B in the y-direction gradually decreases as it moves from the first end e1 connected to the third region A3A towards the second end e2 on the opposite side in the x-direction. The length of the first region A1B in the y-direction changes continuously, for example, as it moves from the first end e1 connected to the third region A3A towards the second end e2 on the opposite side in the x-direction. Furthermore, in the third region A3A, the length W of the end in the x-direction in the y-direction... A3AE The length W of the central part in the x-direction in the y-direction A3AC Short. Additionally, in region A3A, for example, with... Figure 3 Similarly, in the third region A3 shown, the film thickness t at the end in the x-direction is... E The film thickness t in the central part is greater than the x-direction. C The film thickness increases continuously from the central part in the x-direction to the end in the x-direction.

[0096] Similarly, the length of the second region A2B in the y-direction gradually decreases as it moves from the first end e1' connected to the third region A3A to the second end e2' on the opposite side in the x-direction. The length of the first region A2B in the y-direction changes continuously, for example, as it moves from the first end e1' connected to the third region A3A to the second end e2' on the opposite side in the x-direction.

[0097] The domain wall moving element 102 of the third embodiment can achieve the same effects as the domain wall moving element 100 of the first embodiment. Furthermore, by gradually shortening the length of the first region A1B in the y-direction from the first end e1 connected to the third region A3A towards the second end e2 on the opposite side in the x-direction, it is possible to suppress a sharp increase in current density within the first region A1B during data writing, preventing the domain wall DW from reaching the outer end of the element and causing the entire domain wall moving layer 1 to become a single domain. Additionally, by continuously increasing the film thickness from the center of the third region A3 towards the end in the x-direction, it is possible to suppress heat generation caused by current concentration at the corners. Furthermore, by increasing the length W in the y-direction of the end of the third region A3 in the x-direction... A3AE The length W in the y direction of the central part in the x direction of region A3 is greater than that of region A3. A3AC The shorter length of the film can suppress the decrease in current density during data writing at the ends of the third region A3 caused by the increase in film thickness. When the current density during data writing at the ends of the third region A3 is lower than that at the center, it is possible for the domain walls (DW) to be trapped at the ends. These effects can also be achieved when the second region A2B satisfies the above structure.

[0098] Furthermore, this example shows that both region A1B and region A2B have the same shape, but it is also possible that only either region A1B or region A2B has this structure.

[0099] (Fourth implementation)

[0100] Figure 7 This is a cross-sectional view obtained by cutting the domain wall moving element 103 of the fourth embodiment using the xz plane passing through the center of the domain wall moving layer 1 in the y direction. Figure 7 It is along Figure 8 The cross section of line A'-A'. Figure 8 This is a top view obtained by looking down at the magnetic domain wall moving element 103 from the z-direction. Figure 8 In the diagram, dashed lines represent the portions of the first electrode 41, the second electrode 42, and the third electrode 40A that overlap with the magnetoresistive effect section 10. Figure 7The arrow shown is an example of the orientation direction of magnetization in a ferromagnetic material. In the domain wall moving element 103 of the fourth embodiment, the structure of the third electrode 40A differs from that of the first embodiment. In the fourth embodiment, the same reference numerals are used for structures identical to those in the first embodiment, and descriptions are omitted.

[0101] like Figure 7 , Figure 8 As shown, when viewed from above in the z direction, the first surface 40a of the third electrode 40A overlaps entirely with the third region A3, and the outer periphery of the first surface 40a overlaps with the first region A1 and the second region A2. The first surface 40a is the surface of the third electrode 40A closest to the reference layer 3.

[0102] The domain wall moving element 103 of the fourth embodiment can achieve the same effect as the domain wall moving element 100 of the first embodiment. In addition, by arranging the first surface 40a of the third electrode 40A to completely overlap with the third region A3 when viewed from above in the z direction, the flatness of the third region A3 is improved, and the domain wall DW can move smoothly.

[0103] The via diameter is mostly fixed due to the manufacturing process. That is, the choice of via diameter is constrained, and there are cases where it cannot be increased. To increase the number of bits recorded in multi-value data, the third region A3 is preferably as long as possible. By arranging the outer periphery of the first surface 40a of the third electrode 40A to overlap with the first region A1 and the second region A2 when viewed from the z-direction, the aforementioned effect of improving the flatness of the third region A3 can be achieved, and the third region A3 can be maximized within the constraints of the via diameter.

[0104] (Fifth Embodiment)

[0105] Figure 9 This is a top view obtained from the z-direction, looking down at the domain wall moving element 104 of the fifth embodiment. Figure 9 In the figure, the first electrode 41 and the second electrode 42 are indicated by dashed lines. In the domain wall moving element 104 of the fifth embodiment, the structure of the third electrode 40B is different from that of the first embodiment. In the fifth embodiment, the same reference numerals are used for structures that are the same as those in the first embodiment, and descriptions are omitted.

[0106] like Figure 9 As shown, the first surface 40b of the third electrode 40B overlaps entirely with the domain wall moving layer 1 when viewed from the z-direction, wherein the first surface 40b is the surface of the third electrode 40B closest to the reference layer 3. When viewed from the z-direction, the domain wall moving layer 1 is contained within the first surface 40b.

[0107] The domain wall moving element 104 of the fifth embodiment achieves the same effects as the domain wall moving element 100 of the first embodiment. Furthermore, by arranging the first surface 40b of the third electrode 40B, which contains conductive material, to completely overlap with the domain wall moving layer 1 when viewed from the z-direction, the overall heat dissipation of the domain wall moving layer 1, including the first region A1 and the second region A2, is improved. When the overall heat dissipation of the domain wall moving layer 1 is improved, the magnetization fixation function of the first region A1 and the second region A2 is stabilized, and the reliability of data recording is improved.

[0108] (Sixth Embodiment)

[0109] Figure 10 This is a top view obtained from the z-direction, looking down at the magnetic domain wall moving element 105 of the sixth embodiment. Figure 10 In the figure, the first electrode 41 and the second electrode 42 are indicated by dashed lines. In the domain wall moving element 105 of the sixth embodiment, the structure of the third electrode 40C is different from that of the first embodiment. In the sixth embodiment, the same reference numerals are used for structures that are the same as those in the first embodiment, and descriptions are omitted.

[0110] like Figure 10 As shown, the first surface 40c of the third electrode 40C overlaps entirely with the domain wall moving layer 1 when viewed from above in the z direction. The first surface 40c is the surface of the third electrode 40C closest to the reference layer 3, and the maximum length L of the first surface 40c in the y direction is... Y The maximum length L in the x-direction of the first face 40c X Short. When viewed from the z-direction, the magnetic domain wall moving layer 1 is contained within the first surface 40c.

[0111] The domain wall moving element 105 of the sixth embodiment can achieve the same effect as the domain wall moving element 100 of the first embodiment. To increase the number of bits for multi-value data recording, it is preferable that the domain wall moving element has a shape that is longer in one direction. This is achieved by configuring the first surface 40c of the third electrode 40C to completely overlap with the domain wall moving layer 1 when viewed from above in the z direction, and by making the first surface 40c the longest length L in the y direction. Y The maximum length L in the x-direction, which is the direction in which the magnetic domain wall moving layer 1 extends. X The short shape can improve the overall heat dissipation of the domain wall moving layer 1, and the first surface 40c is shaped along the domain wall moving layer 1, which can improve the integration of the domain wall moving element.

[0112] (Seventh Embodiment)

[0113] Figure 11This is a cross-sectional view obtained by cutting the domain wall moving element 106 of the seventh embodiment using the xz plane passing through the center of the domain wall moving layer 1 in the y direction. Figure 11 It is along Figure 12 The cross section of line A”-A”. Figure 12 This is a top view obtained by looking down at the magnetic domain wall moving element 106 from the z-direction. Figure 12 In the diagram, dashed lines represent the portions of the first electrode 41, the second electrode 42, and the third electrode 40D that overlap with the magnetoresistive effect section 10. Figure 11 The arrow shown is an example of the orientation direction of magnetization in a ferromagnetic material. In the domain wall moving element 106 of the seventh embodiment, the structures of the first magnetization fixing layer 20 and the third electrode 40D differ from those of the first embodiment. In the seventh embodiment, the same reference numerals are used for structures identical to those in the first embodiment, and descriptions are omitted.

[0114] like Figure 11 As shown, the film thickness t of the first magnetization fixing layer 20A 20A The film thickness t is greater than that of the second magnetization fixing layer 30. 30 When the thickness t of the first magnetized fixing layer 20A 20A The film thickness t of the second magnetization fixing layer 30 30 At the same time, it is easy to use the difference in coercivity to fix magnetization in different directions.

[0115] The domain wall moving element 106 of the seventh embodiment can achieve the same effect as the domain wall moving element 100 of the first embodiment. For example... Figure 12 As shown, when viewed from above in the z-direction, the third electrode 40D is offset from the center of gravity of the magnetic domain wall moving layer 1. Figure 12 As shown, when viewed from above in the z-direction, the distance L1 between the geometric center O of the first surface 40d of the third electrode 40D and the first magnetized fixing layer 20A is smaller than the distance L2 between the geometric center O of the first surface 40d and the second magnetized fixing layer 30. The first surface 40d is the surface of the third electrode 40D closest to the reference layer 3. The first magnetized fixing layer 20A, which has a thicker film than the second magnetized fixing layer 30, has a higher resistance and is prone to overheating during data writing. By bringing the first surface 40d of the third electrode 40D, which contains conductive material, closer to the first magnetized fixing layer 20A, the heat distribution generated between the first region A1 side and the second region A2 side of the magnetic domain wall moving layer 1 can be suppressed, improving the reliability of data recording. Figure 11 , Figure 12 The diagram shows an example where the first surface 40d overlaps with the first region A1 when viewed from the z-direction. However, it is also possible that the first surface 40d overlaps with both the first region A1 and the second region A2, or that the first surface 40d does not overlap with either the first region A1 or the second region A2.

[0116] (Eighth Embodiment)

[0117] Figure 13 This is a top view obtained from the z-direction, looking down at the vicinity of the first region A1C of the magnetic domain wall moving element 107 in the eighth embodiment. Figure 13 In the figure, the first electrode 41 is indicated by a dashed line. In the domain wall moving element 107 of the eighth embodiment, the structure of the first region A1 is different from that of the first embodiment. In the eighth embodiment, the same reference numerals are used for structures that are the same as those in the first embodiment, and descriptions are omitted.

[0118] like Figure 13 As shown, the first electrode 41 overlaps entirely with the first region A1C when viewed from the z-direction. For example, when viewed from the z-direction, the first region A1C is contained within the first electrode 41. When viewed from the z-direction, the distance between the outer periphery of the first electrode 41 and the outer periphery of the first region A1C is, for example, shortest at the end opposite to the end in the x-direction of the end in the first region A1C that connects to the third region A3 (L). min For example, when viewed from above in the z-direction, the distance between the outer periphery of the first electrode 41 and the outer periphery of the first region A1C varies continuously and is not constant. The distance between the outer periphery of the first electrode 41 and the outer periphery of the first region A1C is minimal at point 1. In the first region A1C, for example, the outer periphery other than the edge connecting to the third region A3 when viewed from above in the z-direction is curved.

[0119] The domain wall moving element 107 of the eighth embodiment achieves the same effect as the domain wall moving element 100 of the first embodiment. By overlapping the first region A1C with the first electrode 41, heat dissipation is improved. However, since the outer periphery of the first electrode 41 is connected to the insulating layer 90, its heat dissipation is worse than that of the central portion of the first electrode 41. By minimizing the distance between the portion of the first region A1C and the outer periphery of the first electrode 41, fluctuations in the magnetization of the first region A1C caused by heat generation can be suppressed, thus improving the reliability of data recording. Figure 13 The diagram shows an example where the distance between the outer periphery of the first electrode 41 and the outer periphery of the first region A1C is shortest at the end opposite to the end in the x-direction of the end in the first region A1C that connects to the third region A3. However, the location where the distance between the outer periphery of the first electrode 41 and the outer periphery of the first region A1C is shortest can be any other location.

[0120] Several embodiments have been given above to illustrate examples of magnetic domain wall moving elements. However, the present invention is not limited to the embodiments described above, and various modifications can be made without changing the spirit of the invention.

[0121] For example, the above illustrates an example where reference layer 3 is located closer to the substrate Sub than magnetic domain wall moving layer 1, but it could also be as follows: Figure 14 As shown in Modified Example 1, the reference layer 3 is located further away from the substrate Sub than the magnetic domain wall moving layer 1. Figure 14 This is a cross-sectional view obtained by cutting the magnetic domain wall moving element 108 of Modified Example 1 with an xz plane passing through the center of its y direction. Figure 14 The structure in which the reference layer 3 is located on the side of the substrate further away than the magnetic domain wall moving layer 1 is called the top fixed structure.

[0122] Alternatively, the characteristic structures of the above-described embodiments and variations can be combined separately.

Claims

1. A magnetic domain wall moving element characterized by comprising a magnetoresistance effect portion, a first electrode, a second electrode, a third electrode, a first magnetization fixed layer, and a second magnetization fixed layer, the magnetoresistance effect portion comprising: a reference layer including a ferromagnetic body; a magnetic domain wall moving layer including a ferromagnetic body; and a nonmagnetic layer sandwiched by the reference layer and the magnetic domain wall moving layer in a first direction, the magnetic domain wall moving layer extending in a second direction orthogonal to the first direction, the magnetic domain wall moving layer comprising: a first region in which a magnetization direction is fixed; a second region in which a magnetization direction is fixed in a direction different from that of the first region; and a third region in which a magnetization direction is variable, located in the second direction at a position sandwiched by the first region and the second region, the first electrode electrically connected to the first region, the second electrode electrically connected to the second region, the third electrode electrically connected to the reference layer and located on a side opposite to the nonmagnetic layer with the reference layer as a reference in the first direction, the first magnetization fixed layer located between the first region and the first electrode for fixing a magnetization of the first region, the second magnetization fixed layer located between the second region and the second electrode for fixing a magnetization of the second region, at least a part of the reference layer overlapping at least one of the first region and the second region when viewed from the first direction, a length of at least one of the first region and the second region in a third direction orthogonal to the first direction and the second direction being shorter than a length of the third region in the third direction, the third region of the magnetic domain wall moving layer being capable of forming a first magnetic domain oriented in a direction in which a magnetization direction is the same as that of the first region and a second magnetic domain oriented in a direction in which a magnetization direction is the same as that of the second region with a magnetic domain wall as a boundary, and the magnetic domain wall moving layer being a layer capable of magnetically recording multivalued data by a change in a magnetic state.

2. The magnetic domain wall moving element according to claim 1, further characterized by comprising a substrate, and the reference layer being closer to the substrate than the magnetic domain wall moving layer.

3. The magnetic domain wall moving element according to claim 1, characterized in that at least one of the first region and the second region has a length in the second direction longer than a length in the third direction.

4. A magnetic domain wall moving element characterized by comprising a magnetoresistance effect portion, a first electrode, a second electrode, a third electrode, a first magnetization fixed layer, and a second magnetization fixed layer, the magnetoresistance effect portion comprising: a reference layer including a ferromagnetic body; a magnetic domain wall moving layer including a ferromagnetic body; and a nonmagnetic layer sandwiched by the reference layer and the magnetic domain wall moving layer in a first direction, the magnetic domain wall moving layer extending in a second direction orthogonal to the first direction, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The magnetic domain wall moving layer includes: a first region in which a magnetization direction is fixed; a second region in which a magnetization direction is fixed in a direction different from the magnetization direction of the first region; and a third region in which a magnetization direction is variable, located in a position sandwiched by the first region and the second region in the second direction, The first electrode is electrically connected to the first region, The second electrode is electrically connected to the second region, The third electrode is electrically connected to the reference layer and is located on the side opposite to the non-magnetic layer with the reference layer as a reference in the first direction, The first magnetization fixing layer is located between the first region and the first electrode for fixing the magnetization of the first region, The second magnetization fixing layer is located between the second region and the second electrode for fixing the magnetization of the second region, The reference layer overlaps at least part of the first region and the second region when viewed from the first direction, A length of at least one of the first region and the second region in a third direction orthogonal to the first direction and the second direction is shorter than a length of the third region in the third direction, At least one of the first region and the second region has: a first part having a length in the third direction longer than a length of the third region in the third direction; and a second part having a length in the third direction shorter than the length of the third region in the third direction, The first part is closer to the third region than the second part in the second direction.

5. The magnetic domain wall moving element according to claim 1, wherein: The length of at least one of the first region and the second region in the third direction gradually decreases from a first end connected to the third region to a second end on the opposite side in the second direction.

6. A magnetic domain wall moving element, comprising: a magnetoresistance effect portion; a first electrode; a second electrode; a third electrode; a first magnetization fixing layer; and a second magnetization fixing layer, wherein the magnetoresistance effect portion includes: a reference layer including a ferromagnetic substance; a magnetic domain wall moving layer including a ferromagnetic substance; and a non-magnetic layer sandwiched by the reference layer and the magnetic domain wall moving layer in a first direction, wherein the magnetic domain wall moving layer extends in a second direction orthogonal to the first direction, wherein the magnetic domain wall moving layer includes: a first region in which a magnetization direction is fixed; a second region in which a magnetization direction is fixed in a direction different from the magnetization direction of the first region; and a third region in which a magnetization direction is variable, located in a position sandwiched by the first region and the second region in the second direction, wherein the first electrode is electrically connected to the first region, wherein the second electrode is electrically connected to the second region, wherein the third electrode is electrically connected to the reference layer and is located on the side opposite to the non-magnetic layer with the reference layer as a reference in the first direction, wherein the first magnetization fixing layer is located between the first region and the first electrode for fixing the magnetization of the first region, and wherein the second magnetization fixing layer is located between the second region and the second electrode for fixing the magnetization of the second region. ​ ​ ​ ​ ​ ​ ​ ​ the second magnetization fixed layer is located between the second region and the second electrode, and functions to fix magnetization of the second region, the reference layer overlaps at least a part of the first region and the second region when viewed from the first direction, a length of a part of at least one of the first region and the second region in a third direction orthogonal to the first direction and the second direction is shorter than a length of the third region in the third direction, a film thickness of an end portion of the third region in the second direction is larger than a film thickness of a central portion of the third region in the second direction, and a length of the end portion in the third direction is shorter than a length of the central portion in the third direction.

7. A magnetic domain wall displacement element comprising: a magnetoresistance effect portion; a first electrode; a second electrode; a third electrode; a first magnetization fixed layer; and a second magnetization fixed layer. the magnetoresistance effect portion includes: a reference layer including a ferromagnetic substance; a magnetic domain wall displacement layer including a ferromagnetic substance; and a nonmagnetic layer sandwiched by the reference layer and the magnetic domain wall displacement layer in a first direction, the magnetic domain wall displacement layer extends in a second direction orthogonal to the first direction, the magnetic domain wall displacement layer includes: a first region in which a magnetization direction is fixed; a second region in which a magnetization direction is fixed in a direction different from a magnetization direction of the first region; and a third region in which a magnetization direction is variable, located in a position sandwiched by the first region and the second region in the second direction, the first electrode is electrically connected to the first region, the second electrode is electrically connected to the second region, the third electrode is electrically connected to the reference layer, and is located on a side opposite to the nonmagnetic layer with the reference layer as a reference in the first direction, the first magnetization fixed layer is located between the first region and the first electrode, and functions to fix magnetization of the first region, the second magnetization fixed layer is located between the second region and the second electrode, and functions to fix magnetization of the second region, the reference layer overlaps at least a part of the first region and the second region when viewed from the first direction, a length of a part of at least one of the first region and the second region in a third direction orthogonal to the first direction and the second direction is shorter than a length of the third region in the third direction, a periphery of a first surface of the third electrode overlaps at least one of the first region and the second region when viewed from the first direction, the first surface being a surface of the third electrode closest to the reference layer.

8. The magnetic domain wall displacement element according to claim 1, wherein: the magnetic domain wall displacement layer is included in a first surface of the third electrode when viewed from the first direction, the first surface being a surface of the third electrode closest to the reference layer.

9. The magnetic domain wall displacement element according to claim 1, wherein: ​ A length of a longest portion of a first surface of the third electrode in the third direction is shorter than a length of a longest portion of the first surface in the second direction, wherein the first surface is a surface of the third electrode closest to the reference layer.

10. A magnetic domain wall displacement element, comprising: a magnetoresistance effect portion; a first electrode; a second electrode; a third electrode; a first magnetization fixed layer; and a second magnetization fixed layer, wherein: the magnetoresistance effect portion includes a reference layer including a ferromagnetic substance; a magnetic domain wall displacement layer including a ferromagnetic substance; and a nonmagnetic layer sandwiched by the reference layer and the magnetic domain wall displacement layer in a first direction, the magnetic domain wall displacement layer extends in a second direction orthogonal to the first direction, the magnetic domain wall displacement layer includes a first region in which a magnetization direction is fixed; a second region in which a magnetization direction is fixed in a direction different from a magnetization direction of the first region; and a third region in which a magnetization direction is variable at a position sandwiched by the first region and the second region in the second direction, the first electrode is electrically connected to the first region, the second electrode is electrically connected to the second region, the third electrode is electrically connected to the reference layer and is located on a side opposite to the nonmagnetic layer with the reference layer as a reference in the first direction, the first magnetization fixed layer is located between the first region and the first electrode and fixes a magnetization of the first region, the second magnetization fixed layer is located between the second region and the second electrode and fixes a magnetization of the second region, at least a portion of the first region and the second region overlaps the reference layer when viewed from the first direction, a length of at least one of the first region and the second region in a third direction orthogonal to the first direction and the second direction is shorter than a length of the third region in the third direction, a film thickness of the first magnetization fixed layer is greater than a film thickness of the second magnetization fixed layer, a distance from a geometric center of a first surface of the third electrode to the first magnetization fixed layer is shorter than a distance from the geometric center of the first surface to the second magnetization fixed layer when viewed from the first direction, wherein the first surface is a surface of the third electrode closest to the reference layer.

11. The magnetic domain wall displacement element according to claim 1, wherein: the first region is included in the first electrode when viewed from the first direction, and a distance from an outer periphery of the first region to an outer periphery of the first electrode is shortest at a first point.

12. A magnetic recording array, comprising: a plurality of the magnetic domain wall displacement elements according to claim 1. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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