An elliptical skyrmion and its identification method

Abstract

This invention discloses an elliptical skyrmion and its identification method, specifically including: inducing a novel elliptical skyrmion in a traditional magnetic interface system by applying external stress or other means; the topological quasiparticle moves directionally to a "cross-shaped" identification end under the drive of an input current; by utilizing the inequivalence of information such as spin helical length and Hall angle of the elliptical skyrmion in different directions, different signals can be read out at the identification end, thus completing the identification of the elliptical skyrmion; furthermore, when the elliptical skyrmion reaches the output end formed by the magnetic tunnel structure, the first resistance state in the original storage unit is adjusted to the second resistance state, thus completing the storage of information.

Description

Technical Field

[0001] This invention belongs to the field of spintronic device technology, and particularly relates to an elliptical skyrmion and its identification method. Background Technology

[0002] The design, construction, and manipulation of material spin structures have always been core topics in spintronics. Compared to traditional ferromagnetic and antiferromagnetic materials, nonlinear magnetic materials possess richer physical connotations and potential application value, and have become a hot topic in spintronics research in recent years. Magnetic skyrmions, as a topologically protected non-collinear magnetic structure with quasi-particle properties, possess numerous advantages such as small size, structural stability, ease of manipulation, and low driving threshold current. They hold great promise as next-generation information carriers for high-capacity, high-speed read / write, low-power, and non-volatile information storage and logic operations, providing a novel physical mechanism for the development of information technology. The chiral spin texture of magnetic skyrmions mainly includes Bloch and Néel types, which, together with the topological structure, determine their physical properties. Therefore, the manipulation of skyrmion spin texture is another hot topic besides its energy and size design, providing new degrees of freedom for research on the physical mechanisms and applications of skyrmion-based magnetic memories.

[0003] Among all the properties affecting the formation of magnetic skyrmions, the Dzyaloshinskii-Moriya (DM) interaction is a crucial magnetic parameter determining their generation, annihilation, size, and current-driven migration velocity. Finding and manipulating materials with strong DM interactions is a key step towards realizing stable, controllable, small-sized, field-free magnetic skyrmions at room temperature, making them the next generation of magnetic storage devices. The generation of DM interactions requires the material system to simultaneously possess spatial inversion symmetry breaking and strong spin-orbit coupling. Current methods for obtaining materials with large DM interactions include: constructing multilayer thin-film heterostructures composed of ferromagnetic and heavy metal films, such as Co / Pt; using two-dimensional magnets to break system symmetry by constructing Janus structures, such as MnXY (X≠Y, X / Y=S / Se / Te); and exploring naturally occurring magnets with symmetry breaking, such as those with... Two-dimensional magnet AX2 protected by crystal symmetry (A: 3d transition metal, X: VI-A or VII-A).

[0004] However, unlike the isotropic DM interactions in the above systems, which in most cases induce round skyrmions, there is still a lack of reports on the generation and identification methods of elliptical skyrmions in the above materials. Summary of the Invention

[0005] This invention proposes an elliptical skyrmion and its identification method. A substrate magnet with anisotropic DM interaction can generate an elliptical skyrmion. When current is input from its left side, the elliptical skyrmion is driven to move to a detection position on its right side for identification. The shape of the skyrmion can be determined by utilizing differential signals such as the different spin helix lengths in different directions. This method can then be applied to information storage, potentially expanding the dimensions of information storage and increasing its capacity. This invention solves the problems of designing, identifying, and applying the novel skyrmion mentioned above.

[0006] The technical solution of the present invention is as follows: an elliptical skyrmion, the elliptical skyrmion comprising a magnetic substrate, an input terminal, a lateral recognition terminal, a longitudinal recognition terminal, and an output terminal;

[0007] The magnetic substrate is used to generate elliptical skyrmions; the magnetic substrate has anisotropic DM interactions; and is capable of generating anisotropic DM interactions under applied stress, wedge structure, or intrinsic special structure.

[0008] The input terminal is used for current input to drive the directional movement of topological quasiparticles in the magnetic substrate;

[0009] The lateral recognition end is used for detecting information in the x-direction of the topological quasiparticles generated in the magnetic substrate, including the spin helix length and Hall angle of the topological quasiparticles.

[0010] The longitudinal recognition end is used for detecting information in the y-direction of the topological quasiparticles generated in the magnetic substrate, including the spin helix length and Hall angle of the topological quasiparticles.

[0011] The output terminal is composed of a ferromagnetic / barrier layer / ferromagnetic tunnel structure, including a reference layer, a barrier layer and a free layer, for reading information from elliptical skyrmions generated by the magnetic substrate.

[0012] Specifically, the material of the magnetic substrate includes any one of Co / Pt, Co / Ir / Pt, or a two-dimensional magnet.

[0013] Specifically, the material of the reference layer in the output terminal includes any one of CoFe, CoFeB, or NiFe.

[0014] Specifically, the material of the barrier layer in the output terminal includes any one of MgO, Al2O3, SiO2, MgAl2O4, AlN, or TiO2.

[0015] Specifically, the material of the free layer in the output terminal includes any one of CoFe, CoFeB, or NiFe.

[0016] The present invention also provides a method for identifying elliptical skyrmions, the method comprising the following steps:

[0017] (1) Apply current to the input end of the topological magnetic structure to drive the directional movement of elliptical skyrmions generated by the magnetic substrate;

[0018] (2) The elliptical skyrmions generated by the magnetic substrate are driven by current to the lateral recognition end and the longitudinal recognition end. Since the spin information carried by the elliptical skyrmions in the lateral and longitudinal directions is different, the spin information read by the recognition end and the recognition end is also different.

[0019] (3) The shape of the skyrmion can be identified by the spin information output by the horizontal and vertical recognition ends, and it can be determined whether it is an elliptical skyrmion.

[0020] Specifically, the spin information fed back by the lateral and longitudinal recognition ends is as follows: the spin helix length and Hall angle information carried by the elliptical skyrmion generated by the magnetic substrate are anisotropic, so the spin information of the two recognition ends are not equivalent.

[0021] Specifically, the stored information at the output terminal includes:

[0022] When the elliptical skyrmions generated by the magnetic substrate do not reach the output terminal, the free layer and the reference layer are arranged in parallel magnetic order, the magnetic tunnel junction is in the first resistive state, and the data written to the storage cell is recorded as "1".

[0023] When the elliptical skyrmions generated by the magnetic substrate reach the output terminal, the magnetic order of the free layer and the reference layer is antiparallel, the magnetic tunnel junction is in the second resistance state, and the data written to the storage cell is recorded as "0".

[0024] An electronic device, comprising:

[0025] One or more processors;

[0026] Memory, used to store one or more programs;

[0027] When the one or more programs are executed by the one or more processors, the one or more processors implement the method for identifying elliptical skyrmions.

[0028] A computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the steps of the method for identifying elliptical skyrmions.

[0029] The beneficial effects of this invention are as follows:

[0030] 1. Based on this invention, a novel topological magnetic structure, the elliptical skyrmion, can be generated.

[0031] 2. A cross-shaped detection structure was constructed using the anisotropic characteristics of elliptical skyrmions, which can accurately detect the presence of elliptical skyrmions.

[0032] 3. Integrating the generation, detection, and information storage of elliptical skyrmions is beneficial for increasing device density and improving storage capacity and efficiency. Attached Figure Description

[0033] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0034] Figure 1 A schematic diagram of a method for generating, identifying, and storing elliptical skyrmions;

[0035] Figure 2 This is a schematic diagram of the Pt / Ir / Co structure according to an embodiment of the present invention;

[0036] Figure 3 This is a diagram showing the intrinsic Pt / Ir / Co interaction intensity and the layer-resolved DM interaction intensity under applied stress, according to an embodiment of the present invention.

[0037] Figure 4 This is a diagram of the intrinsic Pt / Ir / Co magnetic structure and the atomic-level simulated real-space topological magnetic structure under applied stress, according to an embodiment of the present invention.

[0038] Figure reference numerals: 1-Magnetic substrate; 2-Input terminal; 3-Lateral recognition terminal; 4-Vertical recognition terminal; 5-Output terminal; 51-Reference layer; 52-Barrier layer; 53-Free layer. Detailed Implementation

[0039] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application.

[0040] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0041] To more clearly illustrate the technical solutions and advantages of the present invention, embodiments and accompanying drawings are provided for further detailed explanation. Note that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0042] To make the invention's purpose, content, and advantages clearer, this patent will be further described in conjunction with the following drawings and embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0043] Please see Figures 1 to 4 , Figure 1 This invention demonstrates a method for generating, identifying, and storing elliptical skyrmions according to the disclosure of this patent.

[0044] like Figure 1 As shown, an elliptical skyrmion includes a magnetic substrate (1), an input terminal (2), a lateral recognition terminal (3), a longitudinal recognition terminal (4), and an output terminal (5).

[0045] The magnetic substrate (1) is used to generate elliptical skyrmions; the magnetic substrate has anisotropic DM interaction; and is capable of generating anisotropic DM interaction under applied stress, wedge structure or intrinsic special structure;

[0046] The input terminal (2) is used for current input to drive the directional movement of topological quasiparticles in the magnetic substrate (1);

[0047] The lateral recognition end (3) is used for detecting information in the x-direction of the topological quasiparticles generated in the magnetic substrate (1), including the spin helix length and Hall angle of the topological quasiparticles;

[0048] The longitudinal recognition end (4) is used for detecting information in the y-direction of the topological quasiparticles generated in the magnetic substrate (1), including the spin helix length and Hall angle of the topological quasiparticles;

[0049] The output terminal (5) is composed of a ferromagnetic / barrier layer / ferromagnetic tunnel structure, including a reference layer (51), a barrier layer (52) and a free layer (53), for reading information from elliptical skyrmions generated by the magnetic substrate (1).

[0050] The present invention also provides a method for identifying elliptical skyrmions, the method comprising the following steps:

[0051] (1) Apply current to the input end (2) of the topological magnetic structure to drive the directional movement of the elliptical skyrmions generated by the magnetic substrate (1);

[0052] (2) The elliptical skyrmions generated by the magnetic substrate (1) are driven by current to the transverse recognition end (3) and the longitudinal recognition end (4). Since the spin information carried by the elliptical skyrmions in the transverse and longitudinal directions is different, the spin information read by the recognition end (3) and the recognition end (4) is also different.

[0053] (3) The shape of the skyrmion can be identified by the spin information output by the transverse identification end (3) and the longitudinal identification end (4), and it can be determined whether it is an elliptical skyrmion.

[0054] The magnetic substrate (1) generates elliptical skyrmions under the influence of applied stress or gradient operation. Specifically, the magnetic substrate (1) generates anisotropic DM interactions due to its intrinsic properties or under the influence of external factors such as applied stress or constructed gradient structures. That is, the DM interaction coefficients of the system in real space are not equal in different directions, thereby generating elliptical skyrmions. When current is applied from the input terminal (2) to the magnetic substrate (1), the elliptical skyrmions generated by the magnetic substrate (1) are driven by the current to the lateral recognition terminal (3) and the longitudinal recognition terminal (4). The shape of the skyrmions generated by the magnetic substrate (1) is determined by comparing the skyrmion information read from the two output ports. The above operation realizes the generation and recognition of elliptical skyrmions.

[0055] The topological quasiparticle moves towards the recognition end (3) and recognition end (4) under the current drive of the input end (2). The recognition end (3) and recognition end (4) detect and identify the elliptic skyrmion based on the anisotropic signal. The output end (5) is a magnetic tunnel structure containing a reference layer (51), a barrier layer (52), and a free layer (53). When the magnetic substrate (1) does not generate elliptic skyrmions or the elliptic skyrmions do not reach the output end (5), the magnetic order of the reference layer (51) and the free layer (53) of the output end (5) remains parallel. The storage cell maintains the first resistance state and writes data as "1". When the elliptic skyrmion reaches the output end (5), the magnetic order of the reference layer (51) and the free layer (53) remains antiparallel. The storage cell maintains the second resistance state and writes data as "0". At this time, the information reading is completed.

[0056] like Figure 2 As shown, using Pt / Ir / Co as an example, the top and side views of the interface structure are illustrated. In Figure (a), the arrows indicate compressive and tensile stresses applied along the x and y directions, respectively. The stress intensity is defined as (ba) / b, where a and b are the lattice constants in the x and y directions after stress application, respectively.

[0057] like Figure 3As shown, this paper presents the layer-resolved DM interaction strength of a Pt / Ir / Co system obtained by first-principles calculations and spin-helical calculations in real space, under conditions of no external stress interference and an applied stress of 1.5%. Figure (a) is a side view of Pt / Ir / Co; Figure (b) shows the DM interaction strength under no external stress, indicating that the DM interaction originates from the heavy metal Ir layer at the interface between the ferromagnetic and heavy metal systems; Figures (c) and (d) show the DM interaction strength along the x and y directions of the system under 1.5% stress, respectively. These figures show that after applying stress, the DM interaction strength in the x direction is close to that in the initial state and has the same chirality, while the DM interaction strength in the y direction is less than that in the initial state and has the opposite chirality.

[0058] like Figure 4 The diagram illustrates the topological magnetic structure of a Pt / Ir / Co embodiment obtained through atomic-level simulations under no external interference and with an applied stress of 1.5%. The system can generate circular skyrmions under DM interactions without external interference, and elliptical skyrmions are generated under an applied stress of 1.5%. Therefore, stress modulation of the multilayer film structure can induce anisotropic DM interactions, thereby generating elliptical skyrmions.

[0059] The material of the magnetic substrate (1) includes any one of Co / Pt, Co / Ir / Pt or a two-dimensional magnet.

[0060] The material of the reference layer (51) in the output terminal (5) includes any one of CoFe, CoFeB or NiFe.

[0061] The material of the barrier layer (52) in the output terminal (5) includes any one of MgO, Al2O3, SiO2, MgAl2O4, AlN or TiO2.

[0062] The material of the free layer (53) in the output terminal (5) includes any one of CoFe, CoFeB or NiFe.

[0063] The above description is an embodiment of the present invention and does not limit the patent scope of the present invention. Based on the technical solutions disclosed in the present invention, researchers in related fields may directly or indirectly apply the technical content in this field or other related fields, and all such applications shall be within the protection scope of this patent.

[0064] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0065] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

Claims

1. An elliptical skyrmion, characterized in that, The elliptical skyrmion includes a magnetic substrate, an input terminal, a lateral recognition terminal, a longitudinal recognition terminal, and an output terminal; The magnetic substrate is used to generate elliptical skyrmions; the magnetic substrate has anisotropic DM interactions; and is capable of generating anisotropic DM interactions under applied stress, wedge structure, or intrinsic special structure. The input terminal is used for current input to drive the directional movement of topological quasiparticles in the magnetic substrate; The lateral recognition end is used for detecting information in the x-direction of the topological quasiparticles generated in the magnetic substrate, including the spin helix length and Hall angle of the topological quasiparticles. The longitudinal recognition end is used for detecting information in the y-direction of the topological quasiparticles generated in the magnetic substrate, including the spin helix length and Hall angle of the topological quasiparticles. The output terminal is composed of a ferromagnetic / barrier layer / ferromagnetic tunnel structure, including a reference layer, a barrier layer and a free layer, for reading information from elliptical skyrmions generated by the magnetic substrate.

2. An elliptical skyrmion according to claim 1, characterized in that, The material of the magnetic substrate includes any one of Co / Pt, Co / Ir / Pt, or a two-dimensional magnet.

3. An elliptical skyrmion according to claim 1, characterized in that, The material of the reference layer in the output terminal includes any one of CoFe, CoFeB, or NiFe.

4. An elliptical skyrmion according to claim 1, characterized in that, The material of the barrier layer in the output terminal includes any one of MgO, Al2O3, SiO2, MgAl2O4, AlN, or TiO2.

5. An elliptical skyrmion according to claim 1, characterized in that, The material of the free layer in the output terminal includes any one of CoFe, CoFeB, or NiFe.

6. A method for identifying elliptical skyrmions as described in any one of claims 1-5, characterized in that, The method includes the following steps: (1) Apply current to the input end of the topological magnetic structure to drive the directional movement of elliptical skyrmions generated by the magnetic substrate; (2) The elliptical skyrmions generated by the magnetic substrate are driven by current to the lateral recognition end and the longitudinal recognition end. Since the spin information carried by the elliptical skyrmions in the lateral and longitudinal directions is different, the spin information read by the recognition end and the recognition end is also different. (3) The shape of the skyrmion can be identified by the spin information output by the horizontal and vertical recognition ends, and it can be determined whether it is an elliptical skyrmion.

7. The method for identifying elliptical skyrmions according to claim 6, characterized in that, The spin information fed back by the lateral and longitudinal recognition ends is as follows: the spin helix length and Hall angle information carried by the elliptical skyrmion generated by the magnetic substrate are anisotropic, therefore the spin information of the two recognition ends is not equivalent.

8. The method for identifying elliptical skyrmions according to claim 6, characterized in that, The stored information at the output terminal includes: When the elliptical skyrmions generated by the magnetic substrate do not reach the output terminal, the magnetic order of the free layer and the reference layer is parallel, the magnetic tunnel junction is in the first resistive state, and the data written to the storage cell is recorded as "1". When the elliptical skyrmions generated by the magnetic substrate reach the output terminal, the magnetic order of the free layer and the reference layer is antiparallel, the magnetic tunnel junction is in the second resistance state, and the data written to the storage cell is recorded as "0".

9. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method for identifying elliptical skyrmions as described in any one of claims 6-8.

10. A computer-readable storage medium storing computer instructions thereon, characterized in that, When executed by the processor, this instruction implements the steps of the method for identifying elliptical skyrmions as described in any one of claims 6-8.

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