Spin wave transmission channel reconstruction method, computer device and storage medium

Abstract

The present invention discloses a spin wave transmission channel reconstruction method, a computer device and a storage medium. The spin wave transmission channel reconstruction method includes injecting current into a magnon waveguide, controlling the current density and duration of the current, and when the Bloch domain wall moves to the target position, removing the current to allow the Bloch domain wall to relax freely. The present invention can control the position of the Bloch domain wall in the magnon waveguide by injecting current into the magnon waveguide with the Bloch domain wall, thereby reconstructing the spin wave channel and realizing the control of the spin wave transmission path by current; since the current injected into the magnon waveguide directly acts on the device itself, no additional wiring is required, the complexity of the device used is low, and the spin wave channel is controlled by injecting current, so it is suitable for nano devices, so that it is easy to obtain good performance such as high integration brought by small-size devices. The present invention is widely used in the field of electronic device technology.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic devices, and belongs to the field of magnon spin electronics technology, and specifically to a spin wave transmission channel reconstruction method, a computer device and a storage medium. Background Art

[0002] Spin waves are waves formed by the transmission of magnetic moment precession in magnetic materials. They belong to collective excitations in magnets and are also called magnons. Various functional devices that use spin waves as information carriers are often called magnon devices. As information carriers, spin waves have many excellent properties. For example, the wavelength of spin waves is adaptive to the sample size, that is, for a given frequency, the smaller the sample size, the smaller the wavelength of the spin wave. This makes magnon devices easy to miniaturize and can be widely used in micron to nanometer scale devices, naturally adapting to the trend of device miniaturization.

[0003] Magnonic waveguide is the core unit for building magnon devices. Fiber-type magnon waveguide can use the magnetic domain walls inside magnetic materials to transmit spin waves, showing good transmission performance. However, current spin wave transmission technology makes it difficult to control the transmission channel of spin waves, which limits the application of magnon waveguide. Summary of the invention

[0004] In view of at least one of the above technical problems, an object of the present invention is to provide a spin wave transmission channel reconstruction method, a computer device and a storage medium.

[0005] On the one hand, an embodiment of the present invention includes a spin wave transmission channel reconstruction method, comprising:

[0006] Injecting current into the magnon waveguide; the magnon waveguide includes a strip-shaped Bloch domain wall, and the current is injected along a direction parallel to the Bloch domain wall;

[0007] controlling the current density and / or duration of the current;

[0008] When the Bloch domain wall moves to a target position in the magnon waveguide, removing the current to allow the Bloch domain wall to relax freely;

[0009] The spin wave is transmitted by using the Bloch domain wall after free relaxation as a transmission channel.

[0010] Furthermore, the magnon waveguide includes an upper film and a lower film, the upper film is made of a first material, and the lower film is made of a second material; the Bloch domain wall is formed in the upper film; and the upper film and the lower film are stacked to form a nanowire structure.

[0011] Furthermore, the lower film is used to receive the injected current, and the current is injected along the length direction of the lower film.

[0012] Furthermore, the first material is a perpendicular anisotropic ferromagnetic material, and the second material is a heavy metal material.

[0013] Furthermore, the ferromagnetic material satisfies:

[0014] Exchange stiffness coefficient A = 15 pJm -1 , chiral interaction constant D = 3.0 mJm -2 , magnetocrystalline anisotropy constant K u =0.7MJm -3 , saturation magnetization M s =580kAm -1 , damping coefficient α = 0.3, spin Hall angle Φ H =0.13.

[0015] Furthermore, the upper film has a length of 2 μm, a width of 1 μm, and a thickness of 1 nm.

[0016] Furthermore, the method of transmitting the spin wave by using the Bloch domain wall after free relaxation as a transmission channel comprises:

[0017] When the Bloch domain wall reaches a stable state after free relaxation, the control antenna excites a spin wave at the Bloch domain wall.

[0018] Further, controlling the current density and / or duration of the current comprises:

[0019] setting the target position;

[0020] determining a current density time product according to the target position;

[0021] The duration is determined according to the current density-time product and a fixed current density, or the current density is determined according to the current density-time product and a fixed duration.

[0022] On the other hand, an embodiment of the present invention also includes a computer device, including a memory and a processor, wherein the memory is used to store at least one program, and the processor is used to load the at least one program to execute the spin wave transmission channel reconstruction method in the embodiment.

[0023] On the other hand, an embodiment of the present invention further includes a storage medium storing a program executable by a processor, wherein the program executable by the processor is used to execute the spin wave transmission channel reconstruction method in the embodiment when executed by the processor.

[0024] The beneficial effects of the present invention are as follows: the spin wave transmission channel reconstruction method in the embodiment can control the position of the Bloch domain wall in the magnon waveguide by injecting current into the magnon waveguide having the Bloch domain wall, thereby realizing the reconstruction of the spin wave channel and controlling the transmission path of the spin wave by the current; since the current injected into the magnon waveguide directly acts on the device itself, no additional wiring is required, the complexity of the device used is low, and the spin wave channel is controlled by injecting current instead of by a magnetic field, so that the size limitation of micron devices can be broken through and it is applicable to nano devices, so that it is easy to obtain good performance such as high integration brought by small-size devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of the structure of a magnon waveguide in an embodiment;

[0026] Figure 2 and Figure 3 is a diagram showing the simulation effect of injecting current into the magnon waveguide in an embodiment;

[0027] Figure 4 is a flow chart of a spin wave transmission channel reconstruction method in an embodiment;

[0028] Figure 5 This is a simulation effect diagram of the relationship between domain wall velocity and current density in the embodiment. DETAILED DESCRIPTION

[0029] The magnon waveguide in this embodiment is a fiber-type magnon waveguide. Figure 1 , which includes an upper film made of a first material and a lower film made of a second material. A Bloch domain wall is formed in the upper film, and the upper film and the lower film are stacked to form a nanowire structure, which has a smaller length in the y direction and a larger length in the x direction. Specifically, the first material for making the upper film can be a perpendicular anisotropic ferromagnetic material (Ferromagnet, FM), and the second material is a heavy metal material (Heavy metal, HM). The parameters of the ferromagnetic material can be calculated according to Figure 5 The standard selection shown, for example, can select the following parameters:

[0030] Exchange stiffness coefficient A = 15 pJm -1 , chiral interaction constant D = 3.0 mJm -2 , magnetocrystalline anisotropy constant K u =0.7MJm -3 , saturation magnetization M s =580kAm -1 , damping coefficient α = 0.3, spin Hall angle Φ H =0.13.

[0031] Figure 1 The structure of the upper film made of ferromagnetic material is shown, wherein the length of the upper film, i.e., the length in the x-axis direction, is 2 μm, the thickness, i.e., the length in the z-axis direction, is 1 nm, and the width, i.e., the length in the y-axis direction, is 1 μm. The lower film can be arranged on one side of the upper film in the z-axis direction. The size of the lower film can be the same as that of the upper film, i.e., the length of the lower film is 2 μm, the width is 1 μm, and the thickness is 1 nm.

[0032] Reference Figure 1 The two different grayscale parts of the upper film represent two perpendicularly magnetized magnetic domains, and the two magnetic domains are oriented upward and downward respectively. The white part in the middle represents a strip domain wall, which separates the two magnetic domains, that is, the strip domain wall is equivalent to the boundary between the two magnetic domains. The magnetization intensity vector inside the domain wall is arranged parallel to the x-axis (i.e., the extension direction of the domain wall), indicating that the domain wall belongs to the Bloch type, i.e. Figure 1 The domain wall in is a Bloch-type domain wall, as indicated by the arrow labeled m. For a negative current (as indicated by the gray arrow labeled J), the electron spin polarization direction is along +y, as indicated by the black arrow labeled σ.

[0033] In this embodiment, the dynamics of the strip Bloch domain wall in the upper film under the action of current can be described by the following extended Landau-Lifshitz-Gilbert (LLG) equation including the spin-orbit moment:

[0034]

[0035] Where m is the unit vector of magnetization intensity M, γ is the gyromagnetic factor, α is the damping coefficient, t is the time, H eff is the effective magnetic field, T s is the spin-orbit moment.

[0036] According to the above equation, when a current passes through the lower film, a spin current is generated perpendicular to the current direction due to the existence of the spin Hall effect and / or the interface Rashba effect. When the spin current diffuses to the adjacent magnetic layer, it produces a spin-orbit moment on its magnetic moment. That is to say, when the current flows through the nanowire parallel to the long axis, the spin current injected by the spin Hall effect will exert a spin-orbit moment on the magnetization intensity in the magnetic domain wall, and the strip Bloch domain wall in the magnetic nanowire can be moved by the spin-orbit moment. Therefore, the position of the strip Bloch domain wall in the upper film can be controlled by controlling the density and action time of the injected current.

[0037] The process of injecting current into the nanowire along the +x direction is simulated, and the results are as follows: Figure 2 and Figure 3 shown.

[0038] Reference Figure 2 , the duration of the fixed injection current remains unchanged. When there is no injection current, the Bloch domain wall is located in the middle of the upper film; when the injection current density is J = 1.0×10 10 Am -2 When the density of injected current increases to J = 1.0×10 11 Am -2 When , the Bloch domain wall is located in the middle of the upper film close to the upper edge, and the specific current density is J = 1.0 × 10 10 Am -2 When the current direction is +x, the Bloch domain wall is closer to the upper edge. Therefore, it can be concluded that when the duration remains unchanged, the greater the injected current density, the closer the Bloch domain wall is to the edge of the upper film. When the current direction is +x, Figure 2 The Bloch domain wall moves upward. In fact, when the current direction is -x, Figure 2 The middle Bloch domain wall moves downward, so the Bloch domain wall can be moved to any position in the upper film.

[0039] Figure 3 The rectangles in the figure represent the upper film, the white dotted line in the middle represents the central position of the upper film, and the white solid line represents the Bloch domain wall. When the duration of the current action is 0.5ns, the Bloch domain wall is moved to a position deviating from the center of the upper film, that is, it moves to the edge of the upper film; when the density of the fixed injected current is unchanged and the duration of the current action is 0.8ns, the Bloch domain wall is farther from the center of the upper film, that is, closer to the edge of the upper film. It can be concluded that when the duration is constant, the longer the duration of the injected current is, the closer the Bloch domain wall is to the edge of the upper film.

[0040] Figure 3 In the process, when the injection current is stopped after a period of time, the Bloch domain wall maintains the position it reached last, and reaches a stable state after relaxation. At this time, the antenna can be used to excite the spin wave at the Bloch domain wall, so that the spin wave is transmitted in the Bloch domain wall.

[0041] According to the above principle, refer to Figure 4 In this embodiment, the spin wave transmission channel reconstruction method includes the following steps:

[0042] S1. Inject current into the magnon waveguide;

[0043] S2. Controlling the current density and / or duration of the current;

[0044] S3. When the Bloch domain wall moves to the target position in the magnon waveguide, the current is removed to allow the Bloch domain wall to relax freely.

[0045] After executing steps S1-S3, the following steps may also be performed:

[0046] S4. Use the Bloch domain wall after free relaxation as a transmission channel to transmit spin waves.

[0047] In step S1, along the length direction of the lower film, that is, Figure 1 , Figure 2 and Figure 3 The current is injected in the direction parallel to the Bloch domain wall as shown in FIG.

[0048] In step S2, considering that the distance between the target position and the central position of the upper membrane is positively correlated with both the current density of the injected current and the duration of the current, the distance between the target position and the central position of the upper membrane is positively correlated with the product of the current density of the injected current and the duration of the current.

[0049] The current density and domain wall velocity are linearly related within a certain range, and the specific linear relationship is related to the material parameters of the nanowire. Figure 5 As shown, when the chiral interaction constant of the nanowire is D = 5.0 mJm -2 , magnetocrystalline anisotropy constant K u =1.4MJm -3 , the current density is 10×10 11 Am -2 Up to 30×10 11 Am -2 In such an interval, the speed of the domain wall moving toward the edge of the upper film is nearly proportional to the current density; when the material parameters of the nanowire are other values, the current density and the domain wall speed are linearly related in other intervals. In the case of linear approximation, it can be considered that the distance between the target position and the center of the upper film is proportional to the product of the current density of the injected current and the duration of the current. Therefore, the target position that the Bloch domain wall needs to reach can be set first, and the current density-time product P can be determined according to the distance between the target position and the center of the upper film. Then, a fixed current density J can be set according to the actual situation, so as to determine the duration t. Or set a fixed duration t to determine the current density J as

[0050] In step S3, you can refer to Figure 3When the Bloch domain wall moves to the target position in the magnon waveguide, the current is removed to allow the Bloch domain wall to relax freely. When the Bloch domain wall reaches a stable state after free relaxation, the shape and direction of the Bloch domain wall also become stable. Step S4 can be executed to control the antenna so that the antenna excites a spin wave at the Bloch domain wall. The Bloch domain wall serves as a transmission channel for the spin wave, thereby transmitting the spin wave.

[0051] In this embodiment, by injecting current into the magnon waveguide having a Bloch domain wall, the position of the Bloch domain wall in the magnon waveguide can be controlled, thereby reconstructing the spin wave channel and controlling the transmission path of the spin wave by current. Since the spin wave transmission channel reconstruction method in this embodiment controls the spin wave channel by injecting current rather than by a magnetic field, it can break through the size limitation of micron devices and be applicable to nano devices, thereby easily obtaining good performance such as high integration brought by small-size devices.

[0052] In this embodiment, a computer program capable of executing steps S1-S4 can be written and written into a computer device or a storage medium. When the computer device or the storage medium is running, steps S1-S4 can be executed to realize the automated execution of the spin wave transmission channel reconstruction method and obtain the technical effect of the spin wave transmission channel reconstruction method.

[0053] It should be noted that, unless otherwise specified, when a feature is referred to as "fixed" or "connected" to another feature, it may be directly fixed or connected to another feature, or it may be indirectly fixed or connected to another feature. In addition, the descriptions of up, down, left, right, etc. used in this disclosure are only relative to the relative positional relationship of the components of the present disclosure in the accompanying drawings. The singular forms of "a", "said" and "the" used in this disclosure are also intended to include the plural forms, unless the context clearly indicates other meanings. In addition, unless otherwise defined, all technical and scientific terms used in this embodiment have the same meaning as those generally understood by technicians in this technical field. The terms used in the specification of this embodiment are only for describing specific embodiments, not for limiting the present invention. The term "and / or" used in this embodiment includes any combination of one or more related listed items.

[0054] It should be understood that, although the term first, second, third etc. may be adopted to describe various elements in the present disclosure, these elements should not be limited to these terms. These terms are only used to distinguish the same type of elements from each other. For example, without departing from the scope of the present disclosure, the first element may also be referred to as the second element, and similarly, the second element may also be referred to as the first element. The use of any and all examples or exemplary language ("for example", "such as" etc.) provided by the present embodiment is only intended to better illustrate embodiments of the present invention, and unless otherwise required, the scope of the present invention will not be limited.

[0055] It should be appreciated that embodiments of the present invention may be implemented or enforced by computer hardware, a combination of hardware and software, or by computer instructions stored in a non-transitory computer-readable memory. The method may be implemented in a computer program using standard programming techniques - including a non-transitory computer-readable storage medium configured with a computer program, wherein the storage medium so configured causes the computer to operate in a specific and predefined manner - according to the methods and drawings described in the specific embodiments. Each program may be implemented in a high-level procedural or object-oriented programming language to communicate with a computer system. However, if desired, the program may be implemented in an assembly or machine language. In any case, the language may be a compiled or interpreted language. In addition, the program may be run on a programmed ASIC for this purpose.

[0056] In addition, the operations of the process described in this embodiment may be performed in any suitable order, unless otherwise indicated in this embodiment or otherwise clearly contradicted by the context. The process described in this embodiment (or variations and / or combinations thereof) may be performed under the control of one or more computer systems configured with executable instructions, and may be implemented as a code (e.g., executable instructions, one or more computer programs, or one or more applications) executed jointly on one or more processors, by hardware or a combination thereof. The computer program includes a plurality of instructions that may be executed by one or more processors.

[0057] Further, the method can be implemented in any type of computing platform that is operably connected to a suitable computer, including but not limited to a personal computer, a minicomputer, a mainframe, a workstation, a network or distributed computing environment, a separate or integrated computer platform, or in communication with a charged particle tool or other imaging device, etc. Various aspects of the present invention can be implemented in machine-readable code stored on a non-transitory storage medium or device, whether removable or integrated into a computing platform, such as a hard disk, an optical read and / or write storage medium, a RAM, a ROM, etc., so that it can be read by a programmable computer, and when the storage medium or device is read by the computer, it can be used to configure and operate the computer to perform the process described herein. In addition, the machine-readable code, or a portion thereof, can be transmitted via a wired or wireless network. When such media includes instructions or programs that implement the steps described above in conjunction with a microprocessor or other data processor, the invention described in this embodiment includes these and other different types of non-transitory computer-readable storage media. When programmed according to the methods and techniques of the present invention, the present invention also includes the computer itself.

[0058] The computer program can be applied to input data to perform the functions described in the present embodiment, thereby converting the input data to generate output data stored in a non-volatile memory. The output information can also be applied to one or more output devices such as a display. In a preferred embodiment of the present invention, the converted data represents a physical and tangible object, including a specific visual depiction of the physical and tangible object produced on the display.

[0059] The above is only a preferred embodiment of the present invention. The present invention is not limited to the above implementation. As long as the technical effect of the present invention is achieved by the same means, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of protection of the present invention. Within the scope of protection of the present invention, its technical scheme and / or implementation method may have various modifications and changes.

Claims

1. A method for reconstructing a spin wave transmission channel, characterized in that: The spin wave transmission channel reconstruction method comprises: Injecting current into the magnon waveguide; the magnon waveguide includes a strip-shaped Bloch domain wall, and the current is injected along a direction parallel to the Bloch domain wall; controlling the current density and / or duration of the current; When the Bloch domain wall moves to a target position in the magnon waveguide, removing the current to allow the Bloch domain wall to relax freely; The magnon waveguide comprises an upper film and a lower film, wherein the upper film is made of a first material and the lower film is made of a second material; the Bloch domain wall is formed in the upper film; and the upper film and the lower film are stacked to form a nanowire structure; The lower film is used to receive the current injected, and the current is injected along the length direction of the lower film; The first material is a perpendicular anisotropic ferromagnetic material, and the second material is a heavy metal material; The ferromagnetic material satisfies: Exchange stiffness coefficient A = 15 pJm -1 , chiral interaction constant D = 3.0 mJm -2 , magnetocrystalline anisotropy constant K u =0.7MJm -3 , saturation magnetization M s =580kAm -1 , damping coefficient α = 0.3, spin Hall angle Φ H =0.13; The spin wave transmission channel reconstruction method further includes: when the Bloch domain wall reaches a stable state after free relaxation, controlling an antenna to excite a spin wave at the Bloch domain wall.

2. The spin wave transmission channel reconstruction method according to claim 1, characterized in that: The upper film has a length of 2 μm, a width of 1 μm, and a thickness of 1 nm.

3. The spin wave transmission channel reconstruction method according to claim 1, characterized in that: The controlling the current density and / or duration of the current comprises: setting the target position; determining a current density time product according to the target position; The duration is determined according to the current density-time product and a fixed current density, or the current density is determined according to the current density-time product and a fixed duration.

4. A computer device, characterized in that: It comprises a memory and a processor, wherein the memory is used to store at least one program, and the processor is used to load the at least one program to execute the spin wave transmission channel reconstruction method according to any one of claims 1 to 3.

5. A storage medium storing a program executable by a processor, characterized in that: The program executable by the processor is used to execute the spin wave transmission channel reconstruction method described in any one of claims 1 to 3 when executed by the processor.

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