WO2024090370A1 - Élément de déplacement de paroi de domaine magnétique, dispositif de mémoire, et procédé d'écriture de données - Google Patents

Élément de déplacement de paroi de domaine magnétique, dispositif de mémoire, et procédé d'écriture de données Download PDF

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WO2024090370A1
WO2024090370A1 PCT/JP2023/038152 JP2023038152W WO2024090370A1 WO 2024090370 A1 WO2024090370 A1 WO 2024090370A1 JP 2023038152 W JP2023038152 W JP 2023038152W WO 2024090370 A1 WO2024090370 A1 WO 2024090370A1
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domain wall
layer
current
magnetic
wall motion
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Japanese (ja)
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浩太 近藤
義近 大谷
明星 呉
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国立研究開発法人理化学研究所
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/02—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements
    • G11C11/16—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using magnetic elements using elements in which the storage effect is based on magnetic spin effect
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/82—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by variation of the magnetic field applied to the device
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10B—ELECTRONIC MEMORY DEVICES
    • H10B61/00—Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N50/00—Galvanomagnetic devices
    • H10N50/10—Magnetoresistive devices

Definitions

  • the present invention relates to a domain wall motion element, a memory device, and a data writing method.
  • Patent Document 1 describes a method for manufacturing a domain wall motion element in which a magnetization free layer is formed so as to be magnetically coupled with both a first and a second pinning layer whose magnetization directions are fixed in opposite directions, and a domain wall motion region in which the magnetization direction is set to the first direction or the second direction is formed in the magnetization free layer.
  • Magnetic memory devices as non-volatile memories are able to retain internal data even when power is not being supplied, which is a great energy-saving effect.
  • Such magnetic memory devices use ferromagnetic materials, and the magnetic pole information (information on the perpendicular binary state) is recorded internally as digital information.
  • magnetic memory devices using ferromagnetic materials have a limited domain wall motion speed, so there is a limit to how much the operating speed can be improved.
  • the technology described in Patent Document 1 is related to the initialization of domain wall motion elements, and does not solve these problems.
  • the present invention was made in consideration of these problems, and realizes a domain wall motion element, memory device, and data writing method that can improve the domain wall motion speed.
  • the domain wall motion element is made of an antiferromagnetic material having a non-collinear spin structure, and is provided with an antiferromagnetic layer having a domain wall that moves in one direction when a current is applied.
  • the antiferromagnetic material may be any one of Mn3Ge , Mn3Sn , Mn3Ga , Mn3Rh , Mn3Pt , and Mn3Ir .
  • the antiferromagnetic material may have a kagome lattice as a crystal structure, and the one direction in which the domain wall moves may be a direction approximately perpendicular to the normal vector of the plane formed by the kagome lattice.
  • the antiferromagnetic layer may be made of a single crystal.
  • the domain wall motion element may further include a spin Hall layer that contains at least one of Pt, Ta, and W and is stacked on the antiferromagnetic layer, and that exhibits the spin Hall effect when a current is applied.
  • a spin Hall layer that contains at least one of Pt, Ta, and W and is stacked on the antiferromagnetic layer, and that exhibits the spin Hall effect when a current is applied.
  • a memory device includes a domain wall motion element having an antiferromagnetic layer made of an antiferromagnetic material having a non-collinear spin structure, a write unit that writes data into the magnetic domain by determining the magnetization direction of the magnetic domain in the antiferromagnetic layer, and a read unit that reads the magnetization direction of the magnetic domain that has moved within the domain wall motion element by applying a current to the antiferromagnetic layer.
  • the writing unit may have a photoelectric conversion element that outputs an electrical signal according to input light, and may use the electrical signal output by the photoelectric conversion element to control the magnetization direction of the magnetic domain and write data to the magnetic domain.
  • a data writing method includes a first step of writing data to a magnetic domain by controlling the magnetization direction of the magnetic domain of an antiferromagnetic layer made of an antiferromagnetic material having a non-collinear spin structure, and a second step of moving the magnetic domain in one direction of the antiferromagnetic layer by applying a current to the antiferromagnetic layer.
  • the first and second steps may be repeated multiple times.
  • the present invention makes it possible to realize a domain wall motion element, a memory device, and a data writing method that can improve the domain wall motion speed.
  • FIG. 2 is a diagram showing a magnetic structure of a non-collinear antiferromagnetic body according to the first embodiment; FIG. 2 shows the anomalous Hall effect of Mn 3 Ge.
  • FIG. 1 is a diagram showing a method for domain wall motion in a Mn 3 Ge thin wire.
  • FIG. 2 is a diagram showing the magnetic domain wall motion of Mn 3 Ge in time series.
  • 1 is a graph showing the state of domain wall motion in Mn 3 Ge.
  • FIG. 13 is a diagram showing a state when a shift current for moving a domain wall flows in a kagome plane of Mn 3 Ge.
  • 1 is a graph showing the state of domain wall motion in Mn 3 Ge.
  • FIG. 13 is a diagram showing the positional relationship between a shift current and a Kagome surface.
  • FIG. 1 is a diagram illustrating the mechanism of domain wall motion in a ferromagnetic material.
  • 1A and 1B are diagrams illustrating a detailed mechanism of domain wall motion in a ferromagnetic material.
  • FIG. 1 is a diagram showing a detailed mechanism of domain wall motion in Mn 3 Ge. 1 is a graph showing the relationship between the width of a domain wall and the amount of spin accumulation in Mn 3 Ge. 1 is a graph showing the domain wall velocity of each material measured by an experiment.
  • 1A to 1C are configuration diagrams showing variations of domain wall motion elements.
  • FIG. 11 is a schematic configuration diagram of a memory device according to a second embodiment.
  • FIG. 1 is a diagram showing the mechanism of domain wall motion in Mn 3 Ge.
  • FIG. 2 is a block diagram showing a unit relating to control of a register section.
  • FIG. 2 is a detailed configuration diagram of a magnetoresistance element.
  • First embodiment (1A) 1 is a diagram showing the magnetic structure of Mn 3 Ge, an antiferromagnetic material having a non-collinear spin structure (hereinafter also referred to as a non-collinear antiferromagnetic material), which is an element of a domain wall motion element.
  • Mn 3 Ge has a crystal structure in which kagome lattices made of magnetic atoms Mn (manganese) are stacked in the c-axis direction, and FIG. 1 shows the magnetic structure of one kagome plane of the kagome lattice.
  • Ge germanium
  • Mn forms a hexagonal structure on the inside.
  • the direction of the spin of each Mn atom is indicated by an arrow. Note that in Fig. 2 and subsequent figures showing the kagome surface of Mn 3 Ge, the direction of the spin of each Mn atom is similarly indicated by an arrow.
  • Fig. 1(A) the spins of adjacent Mn atoms are offset by 120 degrees from each other.
  • This structure is called an inverted 120-degree structure, and Mn 3 Ge is in an antiferromagnetic order (or chiral antiferromagnetic order).
  • the Mn spins in the entire hexagon exhibit a weak ferromagnetic moment, also called a magnetic octupole, which determines the micromagnetization direction of Mn 3 Ge.
  • the magnetic octupole has a magnetization direction H1 shown as a downward arrow in Fig. 1(A).
  • the orientation of the magnetic octopole is opposite in Fig. 1(A) and (B).
  • the state of Fig. 1(A) and (B) can be switched between each other, so that the non-collinear antiferromagnet can also be used as a memory that records the state of "0" or "1".
  • An antiferromagnet with such a minute magnetization is also called a canted antiferromagnet.
  • Fig. 2 is a diagram showing the anomalous Hall effect of Mn 3 Ge.
  • the kagome planes of Mn 3 Ge are stacked so as to be perpendicular to the [0001] direction, which is the planar direction of the Mn 3 Ge layer M (antiferromagnetic layer).
  • Mn 3 Ge is polarized by magnetic octopoles, so a large virtual magnetic field H is generated in the [01-10] direction in the antiferromagnetic layer M.
  • 3A to 3C show the state of domain wall motion in a thin wire of Mn 3 Ge.
  • a method of domain wall motion in a thin wire of Mn 3 Ge will be described with reference to FIG.
  • the Mn 3 Ge thin wire N has a shape extending in the [2-1-10] direction.
  • a write current C By passing a write current C through this thin wire N in the [0001] direction perpendicular to the [2-1-10] direction, a magnetic domain D1 having magnetic domain walls at both ends is generated.
  • This magnetic domain wall is a Neel wall.
  • a pulse current t having a pulse width on the order of nanoseconds through the thin wire N in the negative direction of [2-1-10]
  • the magnetic domain D1 moves to the position of the magnetic domain D2 shown in FIG. 3A.
  • This pulse current t is also called a shift current.
  • 3B is a diagram showing the magnetic domain wall movement of Mn 3 Ge in a time series.
  • a state in which a magnetic domain (magnetic domain wall) is generated in the thin wire N by the write current C is shown.
  • the magnetic domain moves in the positive direction by the pulse current t.
  • time t3 which is later in the time series than time t2, the magnetic domain moves further in the positive direction by the pulse current t.
  • Fig. 3C is a graph showing the state of domain wall movement in Mn3Ge .
  • data shown by triangular dots indicates data when the direction of the magnetic domain movement distance x and the direction of the pulse current t are positive, and data shown by circular dots indicates data when the direction of the magnetic domain movement distance x and the direction of the pulse current t are negative.
  • the horizontal axis of the graph in Fig. 3C indicates the current density j of the pulse current in the fine wire N, and the vertical axis indicates the domain wall movement speed V.
  • Fig. 3C shows that when the absolute value of the current density j is approximately 4* 1010 (A/ m2 ) or more, the domain wall moves at a constant speed or more.
  • the Mn 3 Ge thin wire can be used as a domain wall motion element.
  • the mechanism of domain wall motion in Mn 3 Ge will be further explained below.
  • FIGS. 3A to 3C are diagram showing a state when a shift current j flows through the kagome surface of Mn 3 Ge to move the domain wall.
  • the kagome surface K is located on the xy plane, and the z-axis direction is defined as the normal direction of the kagome surface K.
  • the x-axis direction is the [2-1-10] direction
  • the y-axis direction is the [01-10] direction
  • the z-axis direction is the [0001] direction.
  • the angle that the vector of the shift current j makes with the z-axis is defined as ⁇ . Note that the domain wall in Mn 3 Ge moves in the opposite direction to the vector direction of the shift current j, as shown in FIGS. 3A to 3C.
  • Fig. 4B is a graph showing the state of domain wall motion in Mn3Ge when ⁇ is 0°, 45°, 60°, and 90°.
  • the horizontal axis of the graph in Fig. 4B indicates the absolute value of the current density j of the shift current, and the vertical axis indicates the domain wall motion speed V.
  • the shift current j flows within the plane of the kagome surface.
  • the spin polarization of Mn 3 Ge related to the shift current j is a non-zero value.
  • the moving domain wall is a Neel domain wall.
  • the vector of the shift current j is perpendicular to the plane of the kagome surface K.
  • the moving domain wall is a Bloch wall.
  • Fig. 4B for any value of ⁇ , as explained in Fig. 3C, it is shown that the larger the absolute value of the shift current j, the greater the movement speed V.
  • Figure 5 shows the mechanism of domain wall movement in a ferromagnetic material.
  • the arrows indicate the direction of spontaneous magnetization (magnetic moment) in the ferromagnetic layer F.
  • the direction of the magnetic moment changes in the center of the ferromagnetic layer F, and this location becomes a domain wall.
  • the right and left sides of the ferromagnetic layer F on either side of the domain wall form different magnetic domains.
  • (II) shows the state in which a shift current flows from the state shown in (I) to the left side of Figure 5.
  • the shift current passes through the domain wall, the electron spin interacts with the magnetic moment, transferring the electron spin angular momentum to the magnetic moment. This causes the magnetic moment to rotate, and the domain wall to move to the right side of Figure 5.
  • This mechanism of transferring spin angular momentum is also called spin transfer torque.
  • (III) shows a state in which the magnetic moment has rotated, and as a result, the magnetic domain wall has moved toward the right side of Fig. 5 compared to (II). If the moving speed of the magnetic domain wall in such a ferromagnetic material is u, then u can be expressed by the following equation. u ⁇ (J P) / Ms ... (1)
  • J is the current density of the shift current
  • P is the spin polarization of the ferromagnetic material
  • Ms is the magnitude of magnetization.
  • Mn 3 Ge which is a non-collinear antiferromagnetic material
  • the domain wall in Mn 3 Ge can move. Therefore, in a non-collinear antiferromagnetic material, the spin polarization is not considered to be a factor in the domain wall movement.
  • Fig. 6A is a diagram showing a detailed mechanism of domain wall movement in a ferromagnetic material.
  • Fig. 6A shows a state in which, when a current j flows through a ferromagnetic material having spontaneous magnetization ⁇ , the magnetic moment in the ferromagnetic material rotates under the torque ⁇ stt derived from the spin angular momentum of electrons described in Fig. 5.
  • the current j flows in the positive direction of the x-axis, and the domain wall moves in the negative direction of the x-axis.
  • Fig. 6B is a diagram showing a detailed mechanism of domain wall motion in Mn 3 Ge, in which when a current j is applied to Mn 3 Ge having a spontaneous magnetization ⁇ , a magnetic octupole of Mn 3 Ge receives a torque ⁇ eff and rotates.
  • Fig. 6C is a graph showing the relationship between the domain wall width L and the spin accumulation amount Sa per unit electric field in Mn 3 Ge.
  • graphs are shown for both the Neel domain wall and the Bloch domain wall.
  • the absolute value of the spin accumulation amount Sa per unit electric field increases as the domain wall width L decreases.
  • the torque ⁇ eff described above increases, and the domain wall can be moved at a higher speed.
  • Fig. 7 is a graph showing the domain wall velocity when various materials are used as the domain wall motion element in an experiment.
  • the vertical axis of the graph in Fig. 7 shows the domain wall motion velocity V at the normalized current density.
  • Fig. 7 shows the following materials: Mn 3 Ge, which is an antiferromagnetic material (AFM); Pt/BiYIG/GSGG, Mn 4-x Ni x N, and GdCo/Pt, which are ferrimagnetic materials (FI); SAF1, SAF2, and SAF3, which are synthetic antiferromagnetic materials (SAF); Pt/Co/AIO x , which are ferromagnetic materials (FM); and permalloy.
  • AFM antiferromagnetic material
  • Pt/BiYIG/GSGG Pt/BiYIG/GSGG
  • Mn 4-x Ni x N and GdCo/Pt
  • FI ferrimagnetic materials
  • SAF1, SAF2, and SAF3 synthetic antiferromagnetic materials
  • SAF1 is TaN/Pt/Co/Ni/Co/Ru/Co/Ni/Co/TaN
  • SAF2 is Ta/Pt/Co/Ni/Co/Ru/Co/Ni/Co/Ta
  • SAF3 is TaN/Pt/Co/Ni/Co/Ru/Ru/Co/Ni/Co/TaN.
  • Mn 3 Ge has an overwhelmingly high domain wall motion velocity V compared to other materials such as ferrimagnetic materials, synthetic antiferromagnetic materials, and ferromagnetic materials. Therefore, by applying Mn 3 Ge to a domain wall motion element, it is possible to improve the domain wall motion velocity.
  • the non-collinear antiferromagnetic material is Mn 3 Ge, but the non-collinear antiferromagnetic material according to the present invention is not limited to Mn 3 Ge.
  • the non-collinear antiferromagnetic material according to the present invention may be another type of compound as long as it is made of an antiferromagnetic material having a non-collinear spin structure and has an antiferromagnetic layer having a domain wall that moves in one direction when a current is applied.
  • An example of another type of compound is a manganese compound, and an example of this is Mn 3 X (X is any of Ge, Sn, Ga, Rh, Pt, Ir, etc.).
  • the thickness of the antiferromagnetic layer (i.e., the thickness of the antiferromagnetic layer in the direction perpendicular to the plane of the antiferromagnetic layer through which the shift current that moves the domain wall flows) may be, for example, on the order of tens to hundreds of nm. Furthermore, the size of the film thickness is not limited to this.
  • the non-collinear antiferromagnetic material used in the domain wall motion element is produced as a single crystal rather than a polycrystal.
  • a single crystal is ideally a crystal in which the direction of the crystal axis is the same in every part of the crystal, but it also includes crystals that partially contain at least either lattice defects or minute changes in the direction of the crystal axis.
  • polycrystals single crystals are stacked in a regular pattern, so pinning sites are less likely to occur and domain walls are more likely to move smoothly.
  • Single crystals can be produced by any known crystal growth method.
  • the non-collinear antiferromagnetic material incorporated in the domain wall motion element may be processed by cutting it out with a focused ion beam (FIB).
  • FIB focused ion beam
  • the domain wall motion element may be created by forming a layer of the non-collinear antiferromagnetic material on the surface of a different object by film deposition.
  • the domain wall motion element can be configured to include an antiferromagnetic layer made of a non-collinear antiferromagnetic material and having a domain wall that moves in one direction when a current is applied.
  • this antiferromagnetic material when a current is applied, spin accumulation is formed around the domain wall, causing the domain wall to move. Due to this mechanism, such an antiferromagnetic material can improve the domain wall motion speed compared to other magnetic materials such as ferrimagnetic materials, synthetic antiferromagnetic materials, and ferromagnetic materials. From another perspective, such an antiferromagnetic material can reduce the current value required to move the domain wall at the same speed compared to other magnetic materials, and therefore can be said to have an energy-saving effect.
  • the antiferromagnetic material may be, for example, any one of Mn3Ge , Mn3Sn , Mn3Ga , Mn3Rh , Mn3Pt , and Mn3Ir .
  • the antiferromagnetic material may have a kagome lattice as a crystal structure, and the direction in which the domain wall moves (or the direction in which the shift current is applied) may be approximately perpendicular to the normal vector of the plane formed by the kagome lattice.
  • the direction in which the domain wall moves may form a vector that is approximately parallel to the kagome plane.
  • approximately parallel means that the direction in which the domain wall moves is parallel to the kagome plane or nearly parallel (for example, the angle between the direction in which the domain wall moves and the kagome plane is a few degrees or less). This can further increase the domain wall motion speed.
  • the antiferromagnetic layer may also be made of a single crystal. This configuration makes it difficult for pinning sites to occur and makes it easier for the domain walls to move smoothly, thereby making it possible to further increase the domain wall movement speed.
  • Fig. 8 is a configuration diagram showing a variation of the domain wall motion element.
  • the domain wall motion element T includes a domain wall motion layer 11 made of Mn 3 Ge, and a spin Hall layer 12 made of Pt (platinum) that is stacked in the z-axis direction on the domain wall motion layer 11.
  • the domain wall motion layer 11 and the spin Hall layer 12 extend on the xy plane and have a predetermined width in the z-axis direction.
  • the domain wall displacement layer 11 is a layer (antiferromagnetic layer) made of Mn 3 Ge, and detailed description of its physical properties is omitted since it is the same as that in (1A).
  • spin Hall effect occurs, in which a flow of electron spins (spin current) occurs in the z-axis direction, which is perpendicular to the x-axis direction.
  • Figure 8 shows a state in which electrons e1 and e2 with different spins move in opposite directions in the z-axis direction.
  • electrons e1 spin-polarized in the negative y-axis direction are accumulated on the negative z-axis side of the spin Hall layer 12 (i.e., the lower side of the spin Hall layer 12 in Figure 8), while electrons e2 spin-polarized in the positive y-axis direction are accumulated on the positive z-axis side of the spin Hall layer 12 (i.e., the upper side of the spin Hall layer 12 in Figure 8).
  • a spin current is generated in the spin Hall layer 12.
  • SOT spin orbit torque
  • This torque can cause the polarity of the magnetic octupole to be reversed. In other words, it becomes possible to write information to the magnetic octupole.
  • the spin Hall layer 12 is made of Pt, but the spin Hall layer 12 is not limited to this and may be made of a material such as a non-magnetic metal or semiconductor that has strong spin-orbit interaction.
  • non-magnetic metals include Pt (platinum), W (tungsten), and Ta (tantalum).
  • the thickness of the domain wall displacement layer 11 (i.e., the width in the z-axis direction) may be on the order of tens to hundreds of nm, as shown in (1A).
  • the thickness of the spin Hall layer 12 may be on the order of tens to tens of nm. The thinner the thickness of the spin Hall layer 12, the less current is required to generate the spin Hall effect, and the greater the energy saving effect. However, to ensure that the spin Hall effect is expressed in the spin Hall layer 12, it is preferable that the spin Hall layer 12 has at least the thickness (e.g., about 10 nm) required for spin-polarized electrons to accumulate on the top and bottom surfaces.
  • the domain wall motion element can be configured to further include a domain wall motion layer 11 and a spin Hall layer 12 having at least one of Pt, Ta, and W stacked on the domain wall motion layer 11, which exhibits the spin Hall effect when a current is applied.
  • a magnetization reversal can be generated at high speed in the domain wall motion layer 11 by passing a current through the spin Hall layer 12. Therefore, when the domain wall motion element T is used as a magnetic memory device, data can be written at high speed to the domain wall motion layer 11.
  • the path of the current flowing through the domain wall motion layer 11 can be separated in the write and read operations of the magnetic memory device. Furthermore, there is no need to apply a magnetic field when reversing magnetization.
  • Embodiment 2 Next, an application example of the domain wall motion element described in the first embodiment will be described.
  • FIG. 9A is a schematic diagram of a memory device to which a domain wall motion element is applied.
  • the memory device is mounted on an ASIC (Application Specific Integrated Circuit) 100, and includes a register section 101 and a data read line 102.
  • ASIC Application Specific Integrated Circuit
  • the register unit 101 writes spin information to the internal memory by a current.
  • the internal memory is a thin wire composed of a layer of Mn 3 Ge, which is a non-collinear antiferromagnetic material, as shown in the first embodiment.
  • a spin-orbit torque is applied from the register unit 101 to the magnetic octupole of the memory, causing magnetization reversal and writing data.
  • the register unit 101 also moves a domain wall by passing a shift current through the memory, realizing another write in a new area of the memory and allowing the reading unit to read data. In this way, the register unit 101 has a function of shifting the magnetization information recorded as data, and is therefore also called a spin shift register.
  • the magnetization information is read by the reading unit of the register unit 101 and then output from the data read line 102 as an electric signal.
  • FIG. 9B is a detailed configuration diagram of the register unit 101.
  • the register unit 101 includes a current generating unit 201 having a conductor 202, a spin Hall layer 203, a magnetoresistance element 204, and a memory line 301.
  • FIG. 9C is a block diagram showing units related to the control of the register section 101.
  • the ASIC 100 includes hardware configurations such as a control section 401, a current measurement circuit 402, and a data output circuit 403.
  • the control unit 401 has a processor 411 and a memory 412.
  • the processor 411 includes one or more processors such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), an FPGA (Field-Programmable Gate Array), a DSP (Digital Signal Processor), etc.
  • Memory 412 is used to store one or more instructions.
  • the one or more instructions are stored in memory 412 as a group of software modules (computer programs).
  • Memory 412 is composed of volatile memory, non-volatile memory, or a combination of both.
  • the number of memories 412 is not limited to one, and multiple memories 412 may be provided.
  • the volatile memory may be, for example, RAM (Random Access Memory) such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory).
  • the non-volatile memory may be, for example, PROM (Programmable ROM), EPROM (Erasable Programmable Read Only Memory), or Flash Memory.
  • the processor 411 is connected to the memory 412, and can perform the following processing executed by the control unit 401 by reading and executing one or more instructions from the memory 412. Note that the memory 412 may be provided outside the processor 411, or may be built into the processor 411.
  • the current measurement circuit 402 and the data output circuit 403 are any type of electrical circuit capable of performing the functions described below.
  • the current generating unit 201 generates an electrical signal for writing information to the memory line 301 via the spin hole layer 203.
  • the current generating unit 201 may have, for example, any photoelectric conversion element. In response to light input to the photoelectric conversion element, this photoelectric conversion element outputs a current, which is an electrical signal.
  • the current generating unit 201 may have a circuit that generates an electrical signal by being controlled by the control unit 401.
  • the conductor 202 of the current generating unit 201 is connected to the spin Hall layer 203, and both ends of the conductor 202 are connected to a power supply voltage and ground, respectively, so that a bias voltage V is applied.
  • the conductor 202 passes a write current Iw corresponding to the electrical signal through the spin Hall layer 203.
  • the spin Hall layer 203 overlaps (i.e., is stacked) with a portion of the memory line 301 perpendicularly, and has the same physical properties and functions as the spin Hall layer 12 described in (1B).
  • a write current Iw flows through the spin Hall layer 203, a spin current is generated therein by the mechanism shown in (1B).
  • the memory line 301 is a domain wall motion element having a domain wall motion layer made of a non-collinear antiferromagnetic material, and has the same physical properties and functions as the domain wall motion layer 11 shown in (1B). Therefore, when a spin orbit torque caused by a spin current is applied to the magnetic octupole of the memory line 301, magnetization reversal occurs, and data is written as magnetization information in the region of the memory line 301 stacked with the spin Hall layer 203. In this way, the current generation unit 201 and the spin Hall layer 203 determine the magnetization direction of the magnetic domain of the memory line 301, and function as a write unit that writes data to that magnetic domain.
  • the magnetization information written is one bit of data, "0" or "1.”
  • FIG. 9B if the magnetization information in the magnetic octupole is pointing upward (positive z-axis direction), it is defined as “0,” and if it is pointing downward (negative z-axis direction), it is defined as "1.”
  • this magnetization information is separated from adjacent magnetization information by a domain wall.
  • a shift current Is (pulse current) is passed through the memory line 301 in the x-axis direction along which the memory line 301 extends.
  • a circuit for passing the shift current Is may be provided inside or outside the ASIC 100. This shift current Is causes the magnetization information to move in the x-axis direction within the memory line 301, as per the mechanism shown in (1A), to the position of the magnetoresistance element 204 separated from the spin Hall layer 203.
  • the timing and duration of the shift current Is can be controlled as desired.
  • FIG. 9D is a detailed configuration diagram of the magnetoresistance element 204.
  • the magnetoresistance element 204 is a magnetic tunnel junction element (MTJ element), and has a memory area 301A that is a partial area of the memory line 301, a nonmagnetic layer 211, and a magnetization fixed layer 212.
  • the memory area 301A, nonmagnetic layer 211, and magnetization fixed layer 212 are stacked in this order in the z-axis direction of FIG. 9B.
  • magnetization M11 information As described above, in memory area 301A, one bit of data "0" or “1” is written to the magnetic octupole as magnetization M11 information.
  • This magnetization M11 information is reversible, and is shown in FIG. 9D as arrows pointing in both directions.
  • the magnetization information stored in memory area 301A changes when shift current Is flows.
  • the non-magnetic layer 211 is made of an insulator such as MgO, and separates the memory area 301A from the magnetization fixed layer 212.
  • the magnetization fixed layer 212 is a layer in which the direction of magnetization M12 is fixed, and is made of, for example, a ferromagnetic material or an antiferromagnetic material.
  • the magnetization fixed layer 212 is made of either a single crystal or a polycrystal. Note that, although the explanation will continue assuming that magnetization M12 faces upward (positive direction of the z-axis) in FIG. 9D, magnetization M12 may also face downward (positive direction of the z-axis).
  • the resistance of the magnetoresistance element 204 is in a low state. However, when the magnetization M11 and the magnetization M12 are in opposite directions (anti-parallel state), the resistance of the magnetoresistance element 204 is in a high state.
  • a first terminal 221 is connected to the surface of the memory area 301A opposite to the surface on which the nonmagnetic layer 211 is laminated, and the drain of a transistor 222 is connected to the first terminal 221.
  • the transistor 222 is, for example, an NMOS (N-channel metal oxide semiconductor) transistor, but may be another type of transistor.
  • the gate of the transistor 222 is connected to the control unit 401 shown in FIG. 9C, and the control unit 401 controls the on and off of the transistor 222.
  • a power supply voltage (not shown) is connected to the source of the transistor 222.
  • a second terminal 223 is connected to the surface of the magnetization fixed layer 212 opposite to the surface on which the nonmagnetic layer 211 is laminated, and a read line 224 is connected to the second terminal 223.
  • the read line 224 is connected to the current measurement circuit 402.
  • the control unit 401 When the control unit 401 turns on the transistor 222, a predetermined voltage is applied to the magnetoresistance element 204. By applying a voltage to the magnetoresistance element 204 in this manner, the control unit 401 passes a read current from the first terminal 221 through the memory area 301A, the nonmagnetic layer 211, the magnetization fixed layer 212, and the second terminal 223 to the read line 224. At this time, even if the voltage value applied to the magnetoresistance element 204 is the same, the current value of the read current changes depending on whether the resistance of the magnetoresistance element 204 is high or low (i.e., depending on whether the magnetoresistance element 204 is in a parallel or anti-parallel state).
  • the current measurement circuit 402 shown in FIG. 9C measures the current value of the read current and outputs the measurement value to the control unit 401.
  • the control unit 401 uses the measurement value to determine whether the magnetoresistance element 204 is in a parallel or anti-parallel state.
  • the control unit 401 determines whether the magnetoresistance element 204 is in a parallel or anti-parallel state, for example, by comparing the magnitude of a predetermined current threshold with the measurement value.
  • the control unit 401 also obtains information on the direction of magnetization M12 of the magnetization fixed layer 212. This information is stored in, for example, the memory 412.
  • the control unit 401 determines whether the information of the magnetization M11 of the memory area 301A indicates "0" or "1” based on the determination result indicating whether the magnetoresistance element 204 is in a parallel or anti-parallel state and the information on the direction of the magnetization M12.
  • the control unit 401 controls the data output circuit 403 to output the determined result of "0" or "1” as an electrical signal from the data read line 102.
  • the magnetoresistance element 204, the current measurement circuit 402, and the control unit 401 function as a reading unit that reads the magnetization information of the memory area 301A.
  • a memory device serving as an ASIC 100 can be configured to include a memory line 301 having a domain wall motion layer made of a non-collinear antiferromagnetic material, a write unit that writes data into the magnetic domain by controlling the magnetization direction of the magnetic domain of the memory line 301, and a read unit that reads the magnetization direction of the magnetic domain that has moved in the memory line 301 by applying a current.
  • the memory device exhibits the effects described in the first embodiment.
  • the memory device may further include a photoelectric conversion element.
  • the writing section of the memory device controls the magnetization direction of the magnetic domains using the electrical signal output by the photoelectric conversion element in response to the input light, and writes data to the magnetic domains. In this way, the memory device is capable of writing data in response to the input light.
  • the present invention can also be considered as a data writing method having a first step of writing data to a magnetic domain in a magnetic domain wall displacement layer made of a non-collinear antiferromagnetic material by controlling the magnetization direction of the magnetic domain, and a second step of moving the magnetic domain in one direction in the magnetic domain wall displacement layer by applying a current to the magnetic domain wall displacement layer.
  • the domain wall motion speed is maximized, and the effect of high-speed data writing can be improved as shown in the first embodiment.
  • the domain wall motion speed is very fast compared to the domain wall motion speed in known materials.
  • the material of the non-collinear antiferromagnetic material constituting the memory line 301 is not limited to Mn 3 Ge, and may be any of the various materials shown in the first embodiment.
  • the ASIC 100 can be applied to any device.
  • the ASIC 100 can be applied to optical communication devices.
  • the input light to the photoelectric conversion element of the current generating unit 201 is, for example, any signal light output from a device other than the ASIC 100.
  • the ASIC 100 can also be applied to other uses, in which case the input light may be light that is not output from the device, such as natural light.
  • the current generating unit 201 is not essential to the ASIC 100.
  • the ASIC 100 may obtain a write current output from a device other than the ASIC 100, and pass the write current directly or after performing any pre-processing to the spin hole layer 203, thereby writing data corresponding to the write current to the memory line 301.
  • the hardware configuration shown in FIG. 9C is not limited to being inside the ASIC 100, but may be provided externally.
  • the non-collinear antiferromagnetic material of the present invention may be configured so that distortion is introduced into the antiferromagnetic layer, ensuring that the degree of freedom of the polarization of the magnetic octupole is two-valued in the direction perpendicular to the film surface. This makes it easier to write and read digital data in a magnetic memory device.
  • the memory device shown in the second embodiment is merely one example, and the domain wall motion element using a non-collinear antiferromagnetic material can be applied to other types of memory devices.
  • the domain wall motion element may be applied to SOT-MRAM (Magnetoresistive Random Access Memory).
  • each of the plurality of memory cells is connected to a bit line and a word line for writing and reading data.
  • Each memory cell has an MTJ element.
  • this MTJ element is formed by sequentially stacking a memory area 301A using a non-collinear antiferromagnetic material, a non-magnetic layer 211, and a magnetization fixed layer 212.
  • the memory area 301A is not configured as a fine line, but is provided individually for each MTJ element (i.e., separated for each MTJ element).
  • a spin-hole layer connected to a bit line and a word line is stacked on the surface formed on the opposite side of the non-magnetic layer 211 in the memory area 301A.
  • a first transistor connected to the spin-hole layer at the drain is connected to the first bit line at its source and to the word line at its gate.
  • a second transistor connected to the spin-hole layer at the drain is connected to the second bit line at its source and to the word line common to the first transistor at its gate.
  • Other aspects of the MTJ element configuration are similar to the magnetoresistance element 204 in embodiment 2, so the description will be omitted.
  • the control unit 401 controls the voltage levels on the bit lines and word lines to perform writing.
  • the control unit 401 sets the voltage level on the word lines to the H level, and sets the voltage level on one of the first bit line and the second bit line to the H level and the voltage level on the other to the L level.
  • the control unit 401 controls the voltage levels of each bit line and word line, thereby storing different digital information in each of the multiple memory cells arranged in a matrix.
  • the control unit 401 also sets the voltage level of the word line to the H level, and sets the voltage level of one of the first bit line and the second bit line to the H level and leaves the other in an open state, thereby passing a read current through the memory cell and reading data. Details of this data reading are as described in the second embodiment, and therefore will not be described here.
  • a domain wall motion element is provided with an antiferromagnetic layer made of an antiferromagnetic material having a non-collinear spin structure, the antiferromagnetic layer having a domain wall that moves in one direction when a current is applied thereto.
  • the antiferromagnetic material is any one of Mn 3 Ge, Mn 3 Sn, Mn 3 Ga, Mn 3 Rh, Mn 3 Pt, and Mn 3 Ir. 2.
  • the antiferromagnetic material has a kagome lattice as a crystal structure, The one direction in which the domain wall moves is a direction substantially perpendicular to a normal vector of a plane formed by the Kagome lattice. 3.
  • the domain wall motion element according to claim 1 or 2. (Appendix 4)
  • the antiferromagnetic layer is made of a single crystal. 4.
  • the domain wall motion element according to claim 1 . (Appendix 5)
  • a spin Hall layer is further provided on the antiferromagnetic layer, the spin Hall layer having at least one of Pt, Ta, and W, and exhibiting a spin Hall effect when a current is applied thereto. 5.
  • the domain wall motion element according to claim 1 is
  • (Appendix 6) a domain wall motion element having an antiferromagnetic layer made of an antiferromagnetic material having a non-collinear spin structure; a writing unit that writes data into the magnetic domains by determining the magnetization direction of the magnetic domains of the antiferromagnetic layer; a reading unit that reads the magnetization direction of the magnetic domain that has moved in the domain wall motion element by applying a current to the antiferromagnetic layer;
  • a memory device comprising: (Appendix 7) the writing unit has a photoelectric conversion element that outputs an electrical signal according to input light, and controls the magnetization direction of the magnetic domain using the electrical signal output by the photoelectric conversion element to write data in the magnetic domain. 7. The memory device of claim 6.
  • (Appendix 8) a first step of writing data to a magnetic domain by controlling the magnetization direction of the magnetic domain of an antiferromagnetic layer made of an antiferromagnetic material having a non-collinear spin structure; a second step of applying a current to the antiferromagnetic layer to move the magnetic domain in one direction across the antiferromagnetic layer;
  • the data writing method includes the steps of: (Appendix 9) Repeating the first and second steps a number of times; 9.
  • M antiferromagnetic layer
  • F ferromagnetic layer
  • T domain wall motion element 11: domain wall motion layer 12: spin Hall layer 100: ASIC 101
  • Register section 102 Data read line 201 Current generating section 202 Conductor 203 Spin Hall layer 204 Magnetoresistance element 211 Nonmagnetic layer 212 Magnetization fixed layer 221 First terminal 222 Transistor 223 Second terminal 224 Read line 301 Memory line 301A Storage area 401 Control section 402 Current measuring circuit 403 Data output circuit 411 Processor 412 Memory

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Abstract

Selon la présente divulgation, il est possible d'obtenir un élément de déplacement de paroi de domaine magnétique apte à améliorer la vitesse de déplacement de paroi de domaine magnétique. Un élément de déplacement de paroi de domaine magnétique selon un mode de réalisation de la présente divulgation comprend une couche antiferromagnétique qui est constituée d'un matériau antiferromagnétique comprenant une structure de spin non colinéaire, et comprend une paroi de domaine magnétique qui se déplace dans une direction par application d'un courant.
PCT/JP2023/038152 2022-10-28 2023-10-23 Élément de déplacement de paroi de domaine magnétique, dispositif de mémoire, et procédé d'écriture de données WO2024090370A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017018391A1 (fr) * 2015-07-24 2017-02-02 国立大学法人東京大学 Élément de mémoire
CN114395791A (zh) * 2021-12-20 2022-04-26 曹桂新 一种具有反常霍尔效应的反铁磁单晶Mn3Sn的制备方法及应用
WO2022158545A1 (fr) * 2021-01-20 2022-07-28 国立大学法人東京大学 Registre à spin photonique, procédé d'écriture d'informations et procédé de lecture d'informations
WO2022224500A1 (fr) * 2021-04-21 2022-10-27 国立大学法人東北大学 Dispositif numérique, son procédé de production et son procédé d'utilisation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017018391A1 (fr) * 2015-07-24 2017-02-02 国立大学法人東京大学 Élément de mémoire
WO2022158545A1 (fr) * 2021-01-20 2022-07-28 国立大学法人東京大学 Registre à spin photonique, procédé d'écriture d'informations et procédé de lecture d'informations
WO2022224500A1 (fr) * 2021-04-21 2022-10-27 国立大学法人東北大学 Dispositif numérique, son procédé de production et son procédé d'utilisation
CN114395791A (zh) * 2021-12-20 2022-04-26 曹桂新 一种具有反常霍尔效应的反铁磁单晶Mn3Sn的制备方法及应用

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
HELENA REICHLOVA: "Imaging and writing magnetic domains in the non-collinear antiferromagnet Mn3Sn", NATURE COMMUNICATIONS, NATURE PUBLISHING GROUP, UK, vol. 10, no. 1, 29 November 2019 (2019-11-29), UK, pages 5459, XP093162253, ISSN: 2041-1723, DOI: 10.1038/s41467-019-13391-z *

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