Magnetic wall utilizing analog memory element and magnetic wall utilizing analog memory

Abstract

A magnetic wall utilization type analog memory element (100) according to the present application includes a magnetic wall driving layer (1) having a magnetic wall (DW), a first region (1a), a second region (1b), and a third region (1c) between the first region and the second region; a magnetization fixed layer (5) disposed in the third region via a non-magnetic layer (6); and a lower electrode layer (4) disposed on a second surface opposite to a first surface of the third region on which the magnetization fixed layer is disposed, at a position overlapping the magnetization fixed layer in a plan view.

Description

[0001] This application is a divisional application of the patent application No. April 14, 2017 , filed in Japan on April 21, 2016, and this patent application is based on and claims priority to that patent application. 201780009225.5 Magnetic wall Magnetic wall utilizing analog storage element and magnetic wall utilizing analog memory TECHNICAL FIELD

[0002] The present application relates to a magnetic wall utilizing type analog memory element and a magnetic wall utilizing type analog memory.

[0003] This application is based on Japanese Patent Application No. 2016-085530 filed on April 21, 2016, and this patent application claims priority to that patent application. BACKGROUND

[0004] As a next generation nonvolatile memory which replaces flash memory and the like that have shown limitations in terms of miniaturization, there are resistance change type memories such as MRAM (Magnetoresistive Random Access Memory), ReRAM (Resistance Random Access Memory), PCRAM (Phase Change Random Access Memory) and the like which store data using resistance change type elements.

[0005] As a method of high density (large capacity) of a memory, in addition to a method of reducing elements themselves which constitute a memory, there is a method of multi-valuing a recording bit of each element which constitutes a memory, and various multi-valuing methods have been proposed (for example, Patent Documents 1 to 3).

[0006] There is a type called a magnetic wall driving type or a magnetic wall moving type for one of MRAM (for example, Patent Document 4). The magnetic wall driving type MRAM performs writing of data by flowing a current in an in-plane direction of a magnetic wall driving layer (or a magnetization free layer), moving a magnetic wall by a spin transfer effect of spin-polarized electrons and flipping magnetization of a ferromagnetic thin film in a direction corresponding to a direction of a writing current.

[0007] In Patent Document 4, a method of multi-valuing or analog storing with respect to the magnetic wall driving type MRAM is described.

[0008] ​​There are proposals for different writing methods of data for MRAM, and in addition to the magnetic wall driving type MRAM, the magnetic field writing type, the yoke magnetic field writing type, the STT (Spin Transfer Torque) type, the SOT (Spin Orbit Torque) type MRAM, and the like are known.

[0009] Prior Art Documents

[0010] Patent Documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2015-088669

[0012] Patent Document 2: International Publication No. 2009 / 072213

[0013] Patent Document 3: Japanese Patent Application Publication No. 2016-004924

[0014] Patent Document 4: International Publication No. 2009 / 101827

[0015] Patent Document 5: International Publication No. 2009 / 054180 SUMMARY

[0016] PROBLEMS TO BE SOLVED BY THE INVENTION

[0017] For the existing magnetic wall driving type MRAM, it is necessary to flow a current in the in-plane direction of the magnetic wall driving layer (or the magnetization free layer) at the time of readout, and therefore there is a possibility that the magnetic wall of the magnetic wall driving layer moves by the current flowing at the time of readout. If the magnetic wall moves to the outside of the portion where the magnetic wall driving layer and the magnetoresistance effect element overlap, the signal becomes a digital signal of 0 or 1 in the magnetic wall driving type MRAM, and it is difficult to use as an analog memory.

[0018] On the contrary, if the magnetic wall has not yet ended moving until the outside of the portion where the magnetic wall driving layer (or the magnetization free layer) and the magnetoresistance effect element overlap when viewed from the top, the magnetic wall moves at the time of readout, and the signal at the initial time of readout changes. That is, for the existing magnetic wall driving type MRAM, even if data can be written in multiple values or analog, there is no method of stably reading out the data. If data written in analog can be stably read out, data written in multiple values can also be stably read out.

[0019] The present application is the result of the persistent efforts made in view of the above-described technical problems, and aims to provide a magnetic wall utilization type analog storage element and a magnetic wall utilization type analog memory capable of stably reading out analog stored data.

[0020] MEANS FOR SOLVING THE PROBLEMS

[0021] The magnetic wall utilization type analog storage element according to the first aspect of the present application is characterized by including: a magnetic wall driving layer having a magnetic wall, a first region, a second region, and a third region between the first region and the second region; a magnetization fixed layer provided in the third region via a non-magnetic layer; and a lower electrode layer provided on a second surface opposite to a first surface of the third region on which the magnetization fixed layer is provided, at a position overlapping the magnetization fixed layer in plan view.

[0022] The magnetic wall utilization type analog storage element according to the second aspect of the present application is characterized in that the magnetic wall utilization type analog storage element according to the first aspect can further include a high resistance layer between the magnetic wall driving layer and the lower electrode layer.

[0023] The magnetic wall utilization type analog storage element according to the third aspect of the present application is characterized in that the magnetic wall driving layer can have a length of 60 nm or more in the magnetic wall utilization type analog storage element according to the first or second aspect.

[0024] The magnetic wall utilization type analog storage element according to the fourth aspect of the present application is characterized in that the magnetic wall utilization type analog storage element according to any one of the first to third aspects can further include a first magnetization supply layer in contact with the first region and having a first magnetization direction, and a second magnetization supply layer in contact with the second region and having a second magnetization direction opposite to the first magnetization direction.

[0025] The magnetic wall utilization type analog storage element according to the fifth aspect of the present application is characterized in that the magnetic wall driving layer, the first magnetization supply layer, the second magnetization supply layer, and the magnetization fixed layer each have a magnetization direction parallel to the respective layers in the magnetic wall utilization type analog storage element according to the fourth aspect.

[0026] The magnetic wall utilization type analog storage element according to the sixth aspect of the present application is characterized in that the magnetic wall driving layer, the first magnetization supply layer, the second magnetization supply layer, and the magnetization fixed layer each have a magnetization direction perpendicular to the respective layers in the magnetic wall utilization type analog storage element according to the fourth aspect.

[0027] The magnetic wall utilization type analog storage element according to the seventh aspect of the present application is characterized in that the magnetic wall driving layer can have a magnetic wall pinning portion in the magnetic wall utilization type analog storage element according to any one of the first to sixth aspects.

[0028] The magnetic wall utilization type analog storage element according to the eighth aspect of the present application is characterized in that the magnetic wall utilization type analog storage element according to any one of the fourth to seventh aspects can be a bipolar element connected to either the first magnetization supply layer or the second magnetization supply layer.

[0029] The ninth aspect of the present application is a magnetic wall utilizing type analog memory including the magnetic wall utilizing type analog memory element according to any one of the first to eighth aspects.

[0030] The tenth aspect of the present application is the magnetic wall utilizing type analog memory according to the ninth aspect, further including a mechanism for reading out a change in resistance between the lower electrode layer and the magnetization fixed layer at the time of reading out.

[0031] The eleventh aspect of the present application is a nonvolatile logic circuit including the magnetic wall utilizing type analog memory in which the magnetic wall utilizing type analog memory elements according to any one of the first to eighth aspects are arranged in an array, and an STT-MRAM, having a storage function and a logic function and including the magnetic wall utilizing type analog memory and the STT-MRAM as the storage function.

[0032] The twelfth aspect of the present application is a magnetic neuron element including the magnetic wall utilizing type analog memory element according to any one of the first to eighth aspects, the third region of the magnetic wall driving layer having a first storage portion and a second storage portion and a third storage portion arranged in a longitudinal direction and sandwiching the first storage portion, and the magnetic neuron element including a current source having a control circuit capable of controlling a flow of a write current so that the magnetic wall moves sequentially in a manner of staying at least once at all of the first storage portion, the second storage portion, and the third storage portion.

[0033] Effects of the Invention

[0034] According to the aspects of the present application, multi-value storage data or analog storage data can be stably read out. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 FIG. 1 is a cross-sectional schematic view of an example of a magnetic wall utilizing type analog memory element according to an embodiment of the present application.

[0036] Figure 2 FIG. 2 is a cross-sectional schematic view of another example of a magnetic wall utilizing type analog memory element according to an embodiment of the present application.

[0037] Figure 3 FIG. 3 is a cross-sectional schematic view of an example of a conventional magnetic wall driving type magnetoresistance effect element.

[0038] Figure 4A FIG. 4 is a cross-sectional schematic view for explaining a method of moving a magnetic wall of a conventional magnetic wall driving type magnetoresistance effect element.

[0039] Figure 4B is a cross-sectional view illustrating a method of moving a magnetic wall in the opposite direction to Figure 4A

[0040] Figure 5 is a cross-sectional view illustrating a path through which a read current flows in a conventional magnetic wall driving type magnetoresistive effect element.

[0041] Figure 6 is a cross-sectional view illustrating a path through which a read current flows in a magnetic wall utilizing type analog storage element of the present application.

[0042] Figure 7 is a cross-sectional view illustrating a principle of writing and reading in a magnetic wall utilizing type analog storage element of the present application.

[0043] Figure 8 is a graph conceptually showing a relationship between a proportion of an area of a portion parallel to a magnetization direction of a magnetization fixed layer and a resistance value of a magnetoresistive effect element portion.

[0044] Figure 9 is a cross-sectional view of a main portion of a cell in a magnetic wall utilizing type analog storage of the present application.

[0045] Figure 10 is a schematic view schematically showing one example of a circuit structure of a magnetic wall utilizing type analog storage of the present application.

[0046] Figure 11 is a cross-sectional view of another example of a magnetic wall utilizing type analog storage element according to an embodiment of the present application.

[0047] Figure 12 is a cross-sectional view of another example of a magnetic wall utilizing type analog storage element according to an embodiment of the present application.

[0048] Figure 13 is a cross-sectional view of one example of a magnetic neuron element according to an embodiment of the present application.

[0049] Figure 14 is a schematic view showing a concept of an artificial brain using a magnetic neuron element according to an embodiment of the present application. DETAILED DESCRIPTION

[0050] ​The following description, with reference to the accompanying drawings, illustrates the structure of a magnetic wall-utilizing analog storage element and a magnetic wall-utilizing analog memory to which the present invention is applied. Furthermore, in the following description, some parts of the drawings used may be enlarged for ease of understanding, and the dimensions and proportions of the various structural elements are not necessarily identical to the actual dimensions. Additionally, the materials and dimensions illustrated in the following description are merely examples, and the present invention is not limited to those examples. Appropriate modifications can be made to implement the present invention within the scope of achieving the effects of the present invention. Other layers may also be included in the elements of the present invention within the scope of achieving the effects of the present invention.

[0051] (Magnetic wall-based analog storage element)

[0052] Figure 1 This is a cross-sectional schematic diagram of an example of a magnetic wall-utilizing analog storage element according to one embodiment of the present invention.

[0053] Figure 1 The magnetic wall-utilizing analog storage element 100 has a magnetic wall DW and includes a magnetic wall driving layer 1 consisting of a first region 1a, a second region 1b, and a third region 1c located between the two regions, a lower electrode layer 4 connected to the third region, and a magnetization fixing layer 5 disposed on the opposite surface of the surface of the third region connected to the lower electrode layer 4 via a non-magnetic layer 6.

[0054] exist Figure 1 The magnetic wall-utilizing analog memory element 100 further includes a first magnetization supply layer 2 connected to the first region 1a and having a first magnetization direction, and a second magnetization supply layer 3 connected to the second region and having a second magnetization direction opposite to the first magnetization direction. Without the first magnetization supply layer 2 and the second magnetization supply layer 3, the write current flowing to the magnetic wall drive layer 1 can be used as a spin polarization current.

[0055] In addition, Figure 1 The magnetic wall-utilizing analog memory element 100 further includes a high-resistivity layer 7 between the magnetic wall driving layer 1 and the lower electrode layer 4. The high-resistivity layer 7 is a layer with a resistivity higher than that of the magnetic wall driving layer 1. Furthermore, the high-resistivity layer 7 prevents the magnetic wall driving from being obstructed when current flows to the lower electrode layer 4 during the driving of the magnetic wall of the magnetic wall driving layer 1. There are no particular limitations on the material of the high-resistivity layer 7 if it is a material capable of achieving the aforementioned preventative function. Even non-magnetic materials are acceptable. The high-resistivity layer 7 can also be a tunnel barrier layer. Therefore, the high-resistivity layer 7 can also be an insulating material that allows tunneling current to flow.

[0056] exist Figure 1In this design, the stacking direction of each layer, i.e., the direction perpendicular to the principal surface of each layer (normal direction), is defined as the Z-direction. Each layer is formed parallel to each other on the XY plane perpendicular to the Z-direction.

[0057] Furthermore, a so-called magnetization-fixed layer refers to a layer whose magnetization direction does not change before and after writing using a write current (the magnetization is fixed). If a layer meets this condition, there are no special limitations on its use.

[0058] The magnetic wall driving layer 1 is a magnetized free layer made of ferromagnetic material, and it is possible to reverse the direction of magnetization. The magnetic wall driving layer 1 has a magnetic wall, and by flowing a current of more than a threshold in the direction (X direction) through the magnetic wall, the spin polarization current generated in the magnetic domain (magnetic region) of the magnetic wall driving layer 1 can move the magnetic wall in the direction through which the conduction electrons flow.

[0059] Each of the first magnetization supply layer 2, the second magnetization supply layer 3, and the magnetization fixing layer 5 is a layer (ferromagnetic layer) made of a magnetized and fixed ferromagnetic material. The first magnetization supply layer 2 and the second magnetization supply layer 3 are arranged to sandwich the magnetic wall drive layer 1 and opposite the magnetization fixing layer 5. Furthermore, the first magnetization supply layer 2 and the second magnetization supply layer 3 are magnetically coupled to the magnetic wall drive layer 1. Data writing occurs when the write current flows from one end of the magnetic wall drive layer 1 to the other.

[0060] exist Figure 1 In the diagram, arrows M1, M2, and M3 indicate the magnetization direction of each layer. Arrows M4 and M5 respectively indicate the magnetization direction of the portion on the side of the first magnetization supply layer 2, with the magnetic wall DW in the magnetic wall drive layer 1 as the boundary, and the magnetization direction of the portion on the side of the second magnetization supply layer 3, with the magnetic wall DW as the boundary.

[0061] exist Figure 1 In the example shown, the magnetic wall driving layer 1, the first magnetization supply layer 2, the second magnetization supply layer 3, and the magnetization fixing layer 5 are in-plane magnetization films with in-plane magnetic anisotropy (in-plane easy magnetization axis), but as... Figure 2 The layers shown can also be perpendicular magnetization films with perpendicular magnetic anisotropy (perpendicular to the easy magnetization axis). Materials that readily form in-plane magnetization films include, for example, NiFe. Additionally, films that readily form perpendicular magnetization films include, for example, Co / Ni laminates.

[0062] If an in-plane magnetized film is used, a large read voltage can be used because it has a high MR ratio and is difficult to write by STT during readout. Furthermore, a vertically magnetized film with high magnetic anisotropy and a small demagnetizing field is preferred when miniaturizing the device. Because of its high tolerance to thermal disturbances, data becomes difficult to erase.

[0063] The following is a description of the principle of the magnetic wall utilization type analog memory element of the present embodiment stably writing data and being capable of reading out.

[0064] The magnetic wall utilization type analog memory element of the present embodiment is, compared with each element of the conventional magnetic wall drive type MRAM, relatively because the magnetic wall movement at the time of reading is sharply suppressed, so it is not possible to achieve an element capable of obtaining a stable analog signal output as with the conventional magnetic wall drive type MRAM.

[0065] Therefore, first, the following is a description of the conventional magnetic wall drive type MARAM.

[0066] The MRAM has a magnetoresistance effect element utilizing a magnetoresistance effect such as a GMR (Giant Magneto Resistance) effect and a TMR (Tunnel Magneto Resistance) effect as a memory cell. The magnetoresistance effect element has, for example, a laminated structure of two ferromagnetic layers sandwiching a non-magnetic layer. The two ferromagnetic layers are a magnetization fixed layer (pin layer) in which the direction of magnetization is fixed and a magnetization free layer (free layer) in which the direction of magnetization is reversible, respectively. The resistance value of the magnetoresistance effect element is larger when the directions of magnetization of the magnetization fixed layer and the magnetization free layer are anti-parallel than when the directions thereof are parallel. In the magnetoresistance effect element as the memory cell of the MRAM, the difference in the resistance value is utilized to correspond the state of parallel by magnetization to data "0" and the state of anti-parallel to data "1", thereby non-volatile storing data. The reading of data is performed by flowing a read current through the magnetoresistance effect element in a form of penetrating the magnetoresistance effect element (in a form of penetrating the laminated structure) and measuring the resistance value of the magnetoresistance effect element. In addition, the writing of data is performed by flowing a spin-polarized current and reversing the direction of magnetization of the magnetization free layer.

[0067] As a mainstream of the data writing method at present, there is known an "STT method" utilizing a spin transfer torque. In the STT method, a spin-polarized current is injected to the magnetization free layer, a torque is generated on the magnetization free layer by the interaction between the spin of the conduction electron bearing the spin-polarized current and the magnetic moment of the magnetization free layer, and the magnetization is reversed in a case where the torque is sufficiently large. The reversal of the magnetization becomes easier to occur as the current density is larger, so it becomes possible to reduce the writing current as the size of the memory cell is reduced.

[0068] In addition, as the STT method, there are known a method in which a write current flows through a tunneling magnetoresistance effect element (see, for example, Patent Literature 1), and a method in which a write current flows in the in-plane direction of a magnetization free layer without making the magnetoresistance effect element tunnel (see, for example, Patent Literature 4).

[0069] In the former method, spin-polarized electrons having the same spin state as that of a magnetization fixed layer are supplied from the magnetization fixed layer to the magnetization free layer, or are pulled from the magnetization free layer to the magnetization fixed layer. As a result, the magnetization of the magnetization free layer is reversed by the spin transfer effect. As described above, according to the direction of the write current through the tunneling magnetoresistance effect element, the magnetization direction of the magnetization free layer can be specified. Further, a magnetic wall driven type magnetic memory provided with a plurality of the former method magnetoresistance effect elements is called a magnetic wall driven type MRAM.

[0070] In addition, with reference to Figure 3 The latter method will be described as follows. Figure 3 is a cross-sectional schematic view showing an example of a conventional magnetic wall driven type magnetoresistance effect element, and if compared with the structure of the magnetic wall driven type analog memory element shown in Figure 1 is different from the structure of the magnetic wall driven type analog memory element shown in

[0071] With respect to the conventional magnetic wall driven type magnetoresistance effect element shown in Figure 3 For the conventional magnetic wall driven type magnetoresistance effect element shown in, the writing of data is performed by moving a magnetic wall DW formed in the magnetization free layer 11. The magnetization free layer 11 has a first region 11a and a second region 11b in which the magnetization is fixed to be substantially antiparallel to each other, and a third region 11c located between the first region 11a and the second region 11b, the direction of the magnetization of the third region 11c becoming substantially parallel to either the first region 11a or the second region. By the constraint of such a magnetization state, a magnetic wall is introduced into the magnetization free layer 11. The magnetic wall can be moved in position by the flow of a current into the magnetization free layer 11.

[0072] For example, in the case of using the magnetic wall driven type MRAM shown in Figure 4AIf current flows from the second magnetization supply layer 3 to the magnetization free layer 11 and further to the first magnetization supply layer 2 in the direction indicated by the dotted line, conduction electrons flow in the direction opposite to the current direction and indicated by the solid line. If the electrons enter from the first magnetization supply layer 2 to the magnetization free layer 11, the electrons become spin-polarized electrons corresponding to the magnetization direction of the magnetic domain of the first magnetization supply layer 2 and the magnetization free layer 11 which are magnetically coupled to the first magnetization supply layer 2. If the spin-polarized electrons reach the magnetic wall, spin transfer occurs in the spin held by the spin-polarized electrons with respect to the magnetic wall, and the magnetic wall moves in the same direction as the flow direction of the conduction electrons. Also, if current flows from the first magnetization supply layer 2 to the magnetization free layer 11 and further to the second magnetization supply layer 3 in the direction indicated by the dotted line, conduction electrons flow in the direction opposite to the current direction and indicated by the solid line. If the electrons enter from the second magnetization supply layer 3 to the magnetization free layer 11, the electrons become spin-polarized electrons corresponding to the magnetization direction of the magnetic domain of the second magnetization supply layer 3 and the magnetization free layer 11 which are magnetically coupled to the second magnetization supply layer 3. If the spin-polarized electrons reach the magnetic wall, spin transfer occurs in the spin held by the spin-polarized electrons with respect to the magnetic wall, and the magnetic wall moves in the same direction as the flow direction of the conduction electrons. Figure 4B

[0073] By the movement of such a magnetic wall, it is possible to make the magnetization of the portion directly below the magnetization fixed layer 5 in the magnetization free layer 11 into a state in which the magnetization direction is parallel to the magnetization direction of the magnetization fixed layer 5 or into a state in which the magnetization direction is anti-parallel. Therefore, information rewriting between the "0" state and the "1" state is possible.

[0074] The readout of data is performed by flowing current between the magnetization fixed layer 5 and the magnetization free layer 11 with the non-magnetic layer 6 interposed therebetween and detecting the resistance change corresponding to the relative angle of the magnetization of the magnetization fixed layer 5 and the magnetization of the magnetization free layer 11. In the magnetization free layer 11, the resistance is low when the magnetization of the portion directly below the magnetization fixed layer 5 is made into a state in which the magnetization direction is parallel to the magnetization direction of the magnetization fixed layer 5, and the resistance is high when the magnetization direction is anti-parallel, and data is discriminated by detecting such a resistance change.

[0075] For the MRAM using the conventional magnetic wall driving type magnetoresistance effect element, the write current of data does not flow through the magnetoresistance effect element (the stacked structure of the magnetization fixed layer 5 and the magnetization free layer 11 with the non-magnetic layer 6 interposed therebetween) but flows in the in-plane direction of the magnetization free layer (the direction parallel to the stacking direction) (see FIG. 2). Figure 3 In the MRAM of the present application, the write current of data flows through the magnetoresistance effect element (the stacked structure of the magnetization fixed layer 5 and the magnetization free layer 11 with the non-magnetic layer 6 interposed therebetween) and the magnetization free layer 11 is magnetized in the direction parallel to the stacking direction.​Figure 4A and Figure 4B ). In addition, the read current of data flows through the magnetic resistance effect element (consisting of the magnetization fixed layer 5 and the magnetization free layer 11 with the non-magnetic layer 6 interposed therebetween) in the stacking direction as shown by the dotted line in FIG. 1, and then flows through a part of the path through which the write current flows (see, for example, Patent Literature 5). That is, a part of the path of the read current overlaps with the path of the write current. Figure 5

[0076] As described above, for the structure of the conventional magnetic wall driving type MRAM, it is necessary for the current to flow in the magnetic wall driving direction (in-plane direction) of the magnetic wall driving layer (magnetization free layer) at the time of read. Therefore, the output signal obtained finally becomes a data signal of 0 or 1. In addition, if the magnetic wall movement does not end until the outside of the portion where the magnetic wall driving layer (magnetization free layer) overlaps with the magnetic resistance effect element portion in plan view, the magnetic wall moves at the time of read and the signal at the time of initial read changes or the like.

[0077] In contrast, the magnetic wall driving type analog memory element of the present embodiment has the lower electrode at the position overlapping with the magnetization fixed layer constituting the magnetic resistance effect element in plan view. Therefore, the read current flows through the magnetic wall driving layer (magnetization free layer) in the perpendicular (face straight) direction as shown by the double dotted line in FIG. 2. Therefore, the read current does not flow in the magnetic wall driving direction (in-plane direction) of the magnetic wall driving layer, so that the magnetic wall movement at the time of read can be suppressed. In addition, since the distance of the magnetic wall driving layer through which the read current flows is short, the magnetic noise can be reduced. Figure 6

[0078] Figure 7 is a cross-sectional schematic view showing the case where the magnetic wall DW is located at the portion 1cA between the magnetization fixed layer 5 and the non-magnetic layer 6 and the lower electrode layer 4 in plan view. In Figure 7 , the tunnel barrier layer 7 and the lower electrode layer 4 are omitted.

[0079] The magnetic wall DW can be moved by the write current (spin-polarized current) flowing in the in-plane direction of the magnetic wall driving layer 1.

[0080] The moving direction of the magnetic wall DW can be set according to the flow direction of the write current (spin-polarized current). That is, when the magnetic wall DW is intended to be moved in the -X direction, the write current (spin-polarized current) is caused to flow in the X direction in a manner that the flow of the spin-polarized electrons hits the magnetic wall DW from the right direction thereof (see, for example, FIG. 3). Figure 4B ​​). In contrast, when the magnetic wall DW is intended to be moved in the X direction, the write current (spin-polarized current) flows in the -X direction in a form that collides with the left side of the magnetic wall DW (refer to FIG. 2). Figure 4A

[0081] In addition, the amount of movement (movement distance) of the magnetic wall DW can be variably controlled by adjusting the size and time of the write current. The size and time of the write current can be set, for example, by the number of pulses or the pulse width.

[0082] As described above, by adjusting the flow direction, size, time, number of pulses, or pulse width of the write current (spin-polarized current), it is possible to move the position of the magnetic wall DW in the magnetic wall driving layer 1 to a desired position.

[0083] In the case where the magnetization fixed layer 5 and the non-magnetic layer 6 are the same size in plan view and the width W in the X direction is the same as the width in the X direction of the lower electrode layer, the portion 1cA of the magnetization fixed layer 5, the non-magnetic layer 6, and the magnetic wall driving layer 1 that substantially overlaps the magnetization fixed layer 5 and the non-magnetic layer 6 in plan view forms a magnetoresistive element 10 (hereinafter referred to as "magnetoresistive element portion"). In the magnetoresistive element 10, the resistance value changes depending on the position of the magnetic wall DW.

[0084] In the case where the magnetization fixed layer 5 and the non-magnetic layer 6 are the same size in plan view and the width W in the X direction is the same as the width in the X direction of the lower electrode layer, the portion 1cA of the magnetization fixed layer 5, the non-magnetic layer 6, and the magnetic wall driving layer 1 that substantially overlaps the magnetization fixed layer 5 and the non-magnetic layer 6 in plan view forms a magnetoresistive element 10 (hereinafter referred to as "magnetoresistive element portion"). In the magnetoresistive element 10, the resistance value changes depending on the position of the magnetic wall DW. Figure 7 When the magnetic wall DW is in the position indicated by the arrow, the magnetoresistive element portion 10 has a parallel circuit of a low resistance portion and a high resistance portion, the low resistance portion being formed by the portion 1cb of the magnetization fixed layer 5, the non-magnetic layer 6, and the magnetic wall driving layer 1 from the magnetic wall DW to the side of the 2nd magnetization supply layer 3 (the portion in which the magnetization direction is parallel to the magnetization direction of the magnetization fixed layer 5), and the high resistance portion being formed by the portion 1ca of the magnetization fixed layer 5, the non-magnetic layer 6, and the magnetic wall driving layer 1 from the magnetic wall DW to the side of the 1st magnetization supply layer 2 (the portion in which the magnetization direction is antiparallel to the magnetization direction of the magnetization fixed layer 5).

[0085] With the above structure, it is possible to output an analog resistance value as the resistance value of the magnetoresistive element portion 10. In addition, by setting the position of the magnetic wall DW to a plurality of positions, it is possible to output a resistance value of a plurality of values corresponding to the number of positions.

[0086] Figure 8 is a graph conceptually showing the relationship between the proportion of the area of the portion 1cb parallel to the magnetization direction of the magnetization fixed layer 5 (corresponding to the position of the magnetic wall DW) and the resistance value of the magnetoresistive element portion 10.

[0087] ​There has been a method of setting a multi-valued resistance value or an analog resistance value by moving the position of a magnetic wall in a magnetic wall driving layer to a desired position, but there has been no method of stably reading out those resistance values.

[0088] In the case of the magnetic wall utilization type analog storage element of the present embodiment, by providing the lower electrode layer through which the readout current passes directly below the magnetization fixed layer 5, it is possible to make the readout current flow through the magnetic wall driving layer in the vertical direction. That is, by making the readout current (flow of spin-polarized electrons) flow in a direction parallel to the magnetic wall, it is possible to relatively drastically reduce the influence on the magnetic wall at the time of readout compared to the prior art. As a result, relatively stable readout is possible compared to the prior art.

[0089] A publicly known material that can be used for a magnetization free layer can be used in the material of the magnetic wall driving layer 1. In particular, a soft magnetic material can be used. For example, a metal selected from Cr, Mn, Co, Fe, and Ni, an alloy containing one or more of these metals, an alloy containing these metals and at least one or more elements selected from B and C and N, and the like can be used. Specifically, Co-Fe, Co-Fe-B, Ni-Fe can be cited.

[0090] The length of the magnetic wall driving layer 1, that is, the length of the first region and the second region and the third region located between the two regions, is preferably 60 nm or more. If it is less than 60 nm, it easily becomes a single magnetic domain and there is a case where it does not have a magnetic wall.

[0091] The thickness of the magnetic wall driving layer 1 is not particularly limited as long as it functions as a magnetic wall driving layer, and for example, it can be 2 to 60 nm. If the thickness of the magnetic wall driving layer 1 becomes 60 nm or more, there is a possibility that a magnetic wall will appear in the stacking direction. However, whether a magnetic wall can appear in the stacking direction is determined by the balance of the shape anisotropy of the magnetic wall driving layer, so the magnetic wall driving layer 1 cannot make the magnetic wall if the thickness is less than 60 nm.

[0092] The magnetic wall driving layer 1 can also have a magnetic wall stopper that prevents the movement of the magnetic wall on the side surface of the layer. The specific structure of the magnetic wall stopper is a publicly known structure, and for example, a concave-convex, a groove, a bulge, a middle thinning, a notch, and the like can be used. By providing such a magnetic wall stopper, it is possible to prevent the movement of the magnetic wall (pinning), and it is possible to make a structure in which the magnetic wall does not move more than that if a current of more than a threshold value does not flow. By the above structure, it is possible to make the output signal non-analog and multi-valued.

[0093] For example, by forming the magnetic wall pinning portion at each prescribed distance, it is possible to more stably hold the magnetic wall, to achieve stable multi-value storage, and to read out an output signal that is more stably multi-valued.

[0094] Among the materials of the magnetization fixing layer 5, known materials that can be used for a magnetization fixing layer can be used. For example, a metal selected from Cr, Mn, Co, Fe, and Ni, and an alloy containing one or more of these metals and exhibiting ferromagnetism can be used. In addition, an alloy containing these metals and at least one or more elements selected from B and C and N can also be used. Specifically, Co-Fe or Co-Fe-B can be cited.

[0095] In addition, in order to obtain a higher output, it is preferable to use a Heusler alloy such as Co2FeSi. A Heusler alloy contains an intermetallic compound having a chemical composition of X2YZ, X is Co, Fe, Ni, or a copper group transition metal element or a noble metal element on the periodic table, Y is a Mn, V, Cr, or Ti group transition metal, and Z is a typical element from group III to group V. For example, Co2FeSi, Co2MnSi, or Co2Mn 1-a Fe a Al b Si 1-b and the like.

[0096] Further, the magnetization fixing layer 5 can also be a composite structure composed of an antiferromagnetic layer, a ferromagnetic layer, and a non-magnetic layer. In the composite structure, the magnetization direction is strongly held by the antiferromagnetic layer, so that the function as a magnetization fixing layer that is difficult to be affected by an external influence can be exercised.

[0097] Further, in the case where the magnetization direction of the magnetization fixing layer 5 is made perpendicular with respect to the stacking surface, it is preferable to use a stacked film of Co and Pt. Specifically, the magnetization fixing layer 5 can be made into [Co (0.24 nm) / Pt (0.16 nm)]6 / Ru (0.9 nm) / [Pt (0.16 nm) / Co (0.16 nm)]4 / Ta (0.2 nm) / FeB (1.0 nm).

[0098] The magnetization of the magnetization of the fixed magnetization layer 5 is fixed in one direction, and the magnetization direction of the magnetic wall drive layer 1 (more precisely, the portion 1cA sandwiched between the fixed magnetization layer 5, the non-magnetic layer 6, and the lower electrode layer 4) varies relatively, thereby functioning as a magnetoresistive effect element 10. The magnetization method of the fixed magnetization layer 5 can use known methods. In the case of use such as a coercivity difference type (pseudo spin valve type) MRAM, the coercivity of the fixed magnetization layer is greater than the coercivity of the magnetic wall drive layer 1. Furthermore, in the case of use such as an exchange bias type (spin valve type) MRAM, the magnetization direction is fixed by the exchange coupling between the fixed magnetization layer 5 and the antiferromagnetic layer.

[0099] In addition, the magnetoresistive effect element 10 functions as a tunnel magnetoresistive (TMR) element when the non-magnetic layer 6 is made of an insulator, and as a giant magnetoresistive (GMR) element when the non-magnetic layer 6 is made of metal.

[0100] The material used for the non-magnetic layer 6 can be any known material that can be used for non-magnetic layers.

[0101] For example, when the non-magnetic layer 6 is composed of an insulator (in the case of a tunnel barrier layer), materials such as Al2O3, SiO2, MgO, MgAl2O4, ZnAl2O4, MgGa2O4, ZnGa2O4, MgIn2O4, ZnIn2O4, and multilayer films and mixed films of these materials can be used. In addition, materials in which a portion of Al, Si, and Mg is replaced by Zn and Be can also be used. Among these, MgO or MgAl2O4 are particularly capable of coherent tunneling, thus enabling highly efficient spin injection.

[0102] In addition, if the non-magnetic layer 6 is made of metal, materials such as Cu, Au, and Ag can be used as its material.

[0103] like Figure 11 As shown, the magnetic bonding layer 8 can also be disposed between the magnetic wall driving layer 1 and the non-magnetic layer 6. The main function of the magnetic wall driving layer 1 is to drive the magnetic wall, and it is not limited to selecting a material suitable for the magnetoresistance effect generated by the non-magnetic layer 6 and the magnetized fixing layer 5. Generally, it is well known that in order to generate the coherent tunneling effect using the non-magnetic layer 6, the magnetized fixing layer 5 or the magnetic bonding layer 8 is preferably a ferromagnetic material with a BCC structure. In particular, it is known that the material used as the magnetized fixing layer 5 or the magnetic bonding layer 8 can achieve a large output when the Co-Fe-B composite material is fabricated by sputtering.

[0104] like Figure 12 As shown, the thickness of the portion of the magnetic wall drive layer 1 overlapping the magnetization fixation layer 5 when viewed from above can be greater than other portions. This is because the current density decreases as the magnetic wall moves below the non-magnetic layer 6 due to its increased area, and the driving speed of the magnetic wall slows down. Therefore, the output analog value can be easily controlled. Furthermore, in fabricating this structure, the magnetic wall drive layer 1, the non-magnetic layer 6, and the magnetization fixation layer 5 are formed using continuous film deposition, removing excess portions. With continuous film deposition, the bonding between the joined layers is strengthened, and more efficient magnetic coupling or output can be obtained.

[0105] The magnetoresistive element section 10 provided in this embodiment can use a known magnetoresistive element structure. For example, each layer can have multiple layers or other layers such as an antiferromagnetic layer that fixes the magnetization direction of the magnetization fixing layer 5.

[0106] The shape of the lower electrode layer 4 is preferably such that the horizontal component of the readout current (spin polarization current) that causes the magnetic wall to move does not appear. When viewed from above, it has the same dimensions as the magnetization fixing layer 5. However, even if the dimensions are not the same, it can still achieve the same effect as conventional magnetic wall driven magnetoresistive effect elements. For example, when viewed from above, the overlap between the lower electrode layer 4 and the magnetization fixing layer 5 is preferably 50% or more, more preferably 90% or more, and even more preferably 100%.

[0107] For example, if the overlap between the lower electrode layer 4 and the magnetized fixing layer 5 is not 100%, there is a possibility that the magnetic wall may move during readout. Whether the magnetic wall will move during readout depends on the position of the overlap between the lower electrode layer 4 and the magnetized fixing layer 5 and the direction of the readout current.

[0108] The material used for the lower electrode layer 4 can be any known material used as an electrode material. For example, aluminum, silver, copper, gold, etc., can be used.

[0109] When the high-resistivity layer 7 is an insulating material, its thickness is preferably 0.8 nm or more, such that the write current does not flow into the lower electrode layer 4. Furthermore, from the viewpoint of preventing write current from flowing into the lower electrode layer 4, it is preferable to have a thickness of 2 nm or less, so as to disregard the effects during the read operation.

[0110] There is no particular limitation on the material of the high-resistance layer 7 as long as it can suppress (substantially prevent) the flow of current for driving the magnetic wall to the lower electrode layer 4 when the magnetic wall of the magnetic wall driving layer 1 is driven. The high-resistance layer 7 can be a tunnel barrier layer, and a known insulating material that can be used for the tunnel barrier layer can be used. For example, Al2O3, SiO2, MgO, MgAl2O4, and the like can be used. In addition to the above, a material in which a part of Al, Si, and Mg is replaced with Zn, Be, or the like can be used. The material of the high-resistance layer 7 can function as long as the specific resistance is higher than that of the magnetic wall driving layer 1. For example, it can be a semiconductor such as Si, SiGe, or Ge, a metal such as bismuth and nickel-chromium alloy, or the like.

[0111] The distance between the end portion of the magnetization fixed layer 5 in the X direction and the end portion of the first magnetization supply layer 2 and the second magnetization supply layer 3 in the X direction can be arbitrarily designed. The magnetic wall in the magnetic wall driving layer 1 has the largest movable range near the end portion of the magnetization fixed layer 5 in contact with the first magnetization supply layer 2 and the second magnetization supply layer 3. This is because the first magnetization supply layer 2 and the second magnetization supply layer 3 are magnetically coupled to the magnetic wall driving layer 1, and even if the magnetic wall is driven to operate, the magnetic wall can be stabilized at the end portion if the energization in the magnetic wall driving layer 1 is stopped. In addition, the magnetic wall moves from the end portion, and does not affect the read output during the period until it moves to the end portion of the magnetization fixed layer 5.

[0112] (Magnetic wall utilization type analog memory)

[0113] The magnetic wall utilization type analog memory of the present embodiment is provided with a plurality of magnetic wall utilization type analog memory elements of the present embodiment.

[0114] In Figure 9 a cross-sectional schematic view of a main part of a cell in the magnetic wall utilization type analog memory is shown.

[0115] Figure 1 The magnetic wall utilization type analog memory elements 100 shown in FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 respectively connect the first wiring 11 and the second wiring 12 on the first magnetization supply layer 2 and the second magnetization supply layer 3. In addition, the third wiring 13 is connected on the magnetization fixed layer 5, and further the fourth wiring 14 is connected on the lower electrode layer 4. The symbol 15 indicates an interlayer insulating layer.

[0116] Figure 10 is a schematic view schematically showing one example of a circuit structure of the magnetic wall utilization type analog memory 1000 according to the present embodiment.

[0117] The first control element 15 is connected to the magnetic wall driving layer 1 via each of the second wirings 12 of the plurality of magnetic wall utilizing analog memory elements 100. The first control element 15 is connected to an external power source not shown, and controls the current flowing to the magnetic wall driving layer 1.

[0118] The first cell selection element 16 is connected to the magnetic wall driving layer 1 via each of the first wirings 11 of the plurality of magnetic wall utilizing analog memory elements 100. One first cell selection element 16 is provided corresponding to one magnetic wall utilizing analog memory element 100. The first cell selection element 16 controls whether to cause the write current to flow to which magnetic wall utilizing analog memory element 100. The first cell selection element 16 is grounded.

[0119] The second control element 17 is connected to the third wiring 13.

[0120] The second control element 17 is connected to an external power source not shown, and controls the current flowing to the third wiring 13.

[0121] The second cell selection element 18 is connected to the lower electrode layer 4 via each of the fourth wirings 14 of the plurality of magnetic wall utilizing analog memory elements 100. One second cell selection element 18 is provided corresponding to one magnetic wall utilizing analog memory element 100. The second cell selection element 18 controls whether to cause the read current to flow to which magnetic wall utilizing analog memory element 100. The second cell selection element 18 is grounded.

[0122] The first control element 15, the second control element 17, the first cell selection element 16, and the second cell selection element 18 can use a known switching element. For example, a transistor element typified by a field effect transistor or the like can be used.

[0123] The first wiring 11, the second wiring 12, the third wiring, and the fourth wiring 14 can use a material used as a general wiring material. For example, aluminum, silver, copper, gold, or the like can be used.

[0124] The following is described with reference to Figure 10 and with the write operation and the read operation of the magnetic wall utilizing analog memory 1000.

[0125] The write operation is controlled by the first control element 15 and the first cell selection element 16.

[0126] First, the first control element 15 is opened (connected) and the opened first cell selection element 16 is selected. The first control element 15 is connected to an external power source and the first cell selection element 16 is grounded. Thus, a write current flows in the order of the first control element 15, the second wiring 12, the second magnetization supply layer 3, the magnetic wall driving layer 1, the first wiring 11, and the selected first cell selection element 16. The case where a current flows in the reverse order is omitted from the description.

[0127] The read-in operation is controlled by the second control element 17 and the second cell selection element 18.

[0128] First, the second control element 17 is opened (connected) and the opened second cell selection element 18 is selected. The second control element 17 is connected to an external power source and the second cell selection element 18 is grounded. Thus, a read-in current flows in the order of the second control element 17, the third wiring 13, the magnetization fixed layer 5, the non-magnetic layer 6, the magnetic wall driving layer 1, the lower electrode layer 4, and the selected second cell selection element 18. The case where a current flows in the reverse order is omitted from the description.

[0129] The second control element 17 and the second cell selection element 18 function as a readout mechanism.

[0130] The magnetic wall utilization type analog memory of the present embodiment can also be configured such that the bipolar element is connected to either the first magnetization supply layer 2 or the second magnetization supply layer 3. With such a configuration, the magnetic wall can be moved in an arbitrary direction by changing the direction of the current.

[0131] The magnetic wall utilization type analog memory element and the magnetic wall utilization type analog memory of the present embodiment can be manufactured using a known manufacturing method, with the main difference from the existing magnetic wall driving type magnetoresistive element and the magnetic wall driving type magnetic memory having such a magnetoresistive element in each cell being the provision of the lower electrode layer (and the tunnel barrier layer).

[0132] (non-volatile logic circuit)

[0133] The non-volatile logic circuit of the present embodiment has the magnetic wall utilization type analog memory of the present embodiment configured in an array, an STT-MRAM, and has a storage function and a logic function, and as the storage function, the above-described magnetic wall utilization type analog memory and STT-MRAM can be provided.

[0134] The magnetic wall utilizing type analog memory and the STT-MRAM are possible to be manufactured by the same process, so cost reduction is possible. In addition, the digital STT-MRAM is provided in the same circuit as the magnetic wall utilizing type analog memory configured in an array shape, so digitization is performed for input and output, and it is possible to form a logic capable of processing in analog inside.

[0135] [Magnetic neuron element]

[0136] Figure 13 Fig. 1 is a cross-sectional schematic view of one example of a magnetic neuron element according to one embodiment of the present application.

[0137] The magnetic neuron element of the present embodiment is provided with the magnetic wall utilizing type analog memory element of the present embodiment, and the third region 1c of the magnetic wall driving layer 1 has the first storage portion 21b, and the second storage portion 21a and the third storage portion 21c arranged in the longitudinal direction sandwiching the first storage portion 21b. In addition, the magnetic neuron element is provided with a current source (not shown) having a control circuit capable of controlling the flow of a write current so that the magnetic wall moves in the order of at least once staying at all of the first storage portion 21b, the second storage portion 21a, and the third storage portion 21c.

[0138] The first storage portion 21b is a portion of the third region 1c of the magnetic wall driving layer 1 overlapping the magnetization fixed layer 5 in plan view, the second storage portion 21a is a portion between the magnetization fixed layer 5 and the first magnetization supply layer 2 (a portion not overlapping the magnetization fixed layer 5 and the first magnetization supply layer 2) in plan view, and the third storage portion 21c is a portion between the magnetization fixed layer 5 and the second magnetization supply layer 3 (a portion not overlapping the magnetization fixed layer 5 and the second magnetization supply layer 3) in plan view.

[0139] The magnetic wall utilizing type analog memory of the present embodiment can be utilized as a magnetic neuron element that functions as an analog synapse. It is preferable for the synapse to have a linear output with respect to a stimulus from the outside. In addition, there is no hysteresis phenomenon when a reverse load is given, and it is preferable to be reversible. As shown in Figure 8 The area of the portion in which the magnetization directions of the magnetization fixed layer 5 and the magnetic wall driving layer 1 are parallel changes continuously by the driving (movement) of the magnetic wall. That is, a parallel circuit is formed by the area of the portion in which the magnetization directions of the magnetization fixed layer 5 and the magnetic wall driving layer 1 are parallel and the area of the portion in which they are anti-parallel. Figure 8The horizontal axis of the graph can be regarded as the driving distance of the magnetic wall, and can represent a relatively linear resistance change. In addition, the driving of the magnetic wall is achieved depending on the time of the current pulse of the applied current magnitude, so the magnitude and direction of the current can be regarded as a load from the outside, in addition to the time of the current pulse in which the current is applied.

[0140] (Initial stage of storage)

[0141] For example, in the case where the magnetic wall of the magnetic wall driving layer 1 moves maximally in the -X direction, the magnetic wall is stabilized at the end portion 21aA on the side of the magnetization fixing layer 5 of the first magnetization supply layer 2. If the current flows from the second magnetization supply layer 3 to the first magnetization supply layer 2, electrons flow from the first magnetization supply layer 2 to the second magnetization supply layer 3, and the electrons that are spin-polarized inside the first magnetization supply layer 2 and the magnetic wall driving layer 11 undergo spin transfer on the magnetic wall, and the magnetic wall moves in the +X direction. Even if the magnetic wall moves until the end portion 21aB on the side of the first magnetization supply layer 2 of the magnetization fixing layer 5 is reached, the resistance of the readout does not change. This state can be referred to as the initial stage of storage. That is, the case where the magnetic wall is disposed inside the second storage portion 21a can be referred to as the initial stage of storage. In the initial stage of storage, storage as data is not implemented, but the state is ready for storage of data.

[0142] (Main storage stage)

[0143] The magnetic wall passes through the lower portion of the magnetization fixing layer 5 (the portion that overlaps when viewed from above) during which the resistance changes as shown in Figure 8 by the current flowing from the second magnetization supply layer 3 to the first magnetization supply layer 2, and becomes a resistance change that is approximately proportional to the load at the time of readout. This is the main storage stage. That is, the case where the magnetic wall is disposed inside the first storage portion 21b can be referred to as the main storage stage of storage. The state where the magnetic wall is outside the end portion of the magnetization fixing layer 5 can be defined as storage or as no storage, and the state where the magnetic wall is outside the end portion of the magnetization fixing layer 5 on the opposite side can be defined as no storage or as storage. Of course, if the current flowing between the second magnetization supply layer 3 and the first magnetization supply layer 2 is reversed, the opposite effect occurs.

[0144] (Deepening stage of storage)

[0145] The magnetic wall reaches the end portion 21cB of the second magnetization supply layer 3 of the magnetization fixing layer 5 and even if the movement in the direction away from the magnetization fixing layer 5 is performed, the output at the time of read-in does not change. However, even if the reverse load is applied after the magnetic wall completely departs from the magnetization fixing layer 5, the output at the time of read-in does not change until the magnetic wall reaches the end portion 21cB of the magnetization fixing layer 5. That is, it means that even if the load from the outside is given, the storage is not lost, and this can be called as a deepening stage of storage. That is, the case where the magnetic wall is disposed in the third storage portion 21c can be called as a deepening stage of storage.

[0146] If the current flowing between the second magnetization supply layer 3 and the first magnetization supply layer 2 is reverse, the correspondence of the initial stage of storage, the main storage stage, and the deepening stage of storage to each storage portion becomes reverse.

[0147] In order to use the magnetic wall utilization type analog memory of the present embodiment as an element which acts as an analog synapse and as a magnetic neuron element of the present embodiment, a current source which can flow the write current in a form of sequentially making the movement of the magnetic wall pass through the initial stage of storage, the main storage stage, and the deepening stage of storage is required. That is, a current source (not shown) having a control circuit which controls the write current so that the magnetic wall moves in a form of at least once staying in the first storage portion, the second storage portion, and the third storage portion all of the storage portions in order is required.

[0148] According to the condition of the write current, it is possible to determine whether the magnetic wall passes through each of the first storage portion, the second storage portion, and the third storage portion by multiple times of movement.

[0149] (Forget stage of storage)

[0150] By moving the magnetic wall of the magnetic wall drive layer 1 in the non-storage state, it is possible to forget the storage. In addition, even if the driving or disappearance of the magnetic wall is caused by giving the external magnetic field and heat and physical distortion, the information between the magnetic wall utilization type analog memories loses the association. These can be called as the forget stage of storage.

[0151] (Artificial brain using magnetic neuron element)

[0152] The magnetic neuron element of the present embodiment is a memory that simulates the activity of a synapse and is capable of passing through an initial stage of storage, a main storage stage, and a deepened stage of storage. The analog memory of the present embodiment using a magnetic wall is provided on a plurality of circuits, and it is possible to perform simulation of a brain. It is possible to form a brain with high integration as the array is configured equally in the vertical and horizontal directions as with a general memory.

[0153] In addition, as shown in Figure 14 the plurality of magnetic neuron elements holding specific circuits are configured as one block, it is possible to form a brain with different degrees of recognition from external loads in terms of the array configuration. For example, it is possible to give birth to a brain with high sensitivity to color or a brain with high understanding of language, and the like. In summary, it is possible to perform a processing of recognizing the five senses area in which information from an external sensor is optimized for vision, taste, touch, smell, and hearing, and further form a process called a decision-making process for the next action by making a judgment in a logical thinking area. Furthermore, because the driving speed of the magnetic wall with respect to a load or the formation method of the magnetic wall changes if the material of the magnetic wall driving layer 1 is changed, it is possible to form an artificial brain that takes this change as personality.

[0154] Symbol Explanation

[0155] 1. Magnetic wall driving layer

[0156] 1a. First region

[0157] 1b. Second region

[0158] 1c. Third region

[0159] 2. First magnetization supply layer

[0160] 3. Second magnetization supply layer

[0161] 4. Lower electrode layer

[0162] 5. Magnetization fixing layer

[0163] 6. Non-magnetic layer

[0164] 7. Tunnel barrier layer

[0165] 8. Magnetic coupling layer

[0166] 21a. Second storage portion

[0167] 21b. First storage portion

[0168] 21c. Third storage portion

[0169] 100. Magnetic wall utilizing analog memory element

[0170] 1000. Magnetic wall utilizing analog memory

Claims

1. A magnetic wall utilizing analog memory element characterized by comprising: a magnetic wall driving layer having a magnetic wall, a first region, a second region, and a third region between the first region and the second region; a magnetization fixed layer provided in the third region via a non-magnetic layer; a lower electrode layer provided on a second surface opposite to a first surface of the third region on which the magnetization fixed layer is provided, at a position overlapping the magnetization fixed layer in plan view; and a high resistance layer provided between the magnetic wall driving layer and the lower electrode layer, wherein a thickness of a portion of the magnetic wall driving layer overlapping the magnetization fixed layer in plan view is greater than a thickness of other portions, wherein a length of the magnetic wall driving layer is 60 nm or more, wherein the magnetic wall utilizing analog memory element further comprises: a first magnetization supply layer in contact with the first region and having a first magnetization direction; and a second magnetization supply layer in contact with the second region and having a second magnetization direction opposite to the first magnetization direction, and wherein the magnetic wall driving layer has a magnetic wall stopper formed at each predetermined distance and constituted by a concave-convex, a groove, a protrusion, or a notch.

2. The magnetic wall utilizing analog memory element according to claim 1, characterized in that the magnetization directions of the magnetic wall driving layer, the first magnetization supply layer, the second magnetization supply layer, and the magnetization fixed layer are respectively parallel to each layer.

3. The magnetic wall utilizing analog memory element according to claim 1, characterized in that the magnetization directions of the magnetic wall driving layer, the first magnetization supply layer, the second magnetization supply layer, and the magnetization fixed layer are respectively perpendicular to each layer.

4. The magnetic wall utilizing analog memory element according to claim 2 or 3, characterized in that a bipolar element is connected to either the first magnetization supply layer or the second magnetization supply layer.

5. A magnetic wall utilizing analog memory characterized by comprising a plurality of the magnetic wall utilizing analog memory elements according to any one of claims 1 to 4.

6. A nonvolatile logic circuit characterized by comprising a magnetic wall utilizing analog memory in which the magnetic wall utilizing analog memory elements according to any one of claims 1 to 4 are arranged in an array, and a spin transfer torque type magnetoresistive random access memory, and having a storage function and a logic function and having the magnetic wall utilizing analog memory and the spin transfer torque type magnetoresistive random access memory as the storage function.

7. A magnetic neuron element characterized by comprising the magnetic wall utilizing analog memory element according to any one of claims 1 to 4, wherein the third region of the magnetic wall driving layer has a first storage portion and a second storage portion and a third storage portion arranged in a longitudinal direction and sandwiching the first storage portion, and wherein the magnetic neuron element comprises a current source having a control circuit capable of controlling a flow of a write current so that a magnetic wall can move in an order in which the magnetic wall stays at least once in all of the first storage portion, the second storage portion, and the third storage portion. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Images