A multi-state magnetic random access memory

Abstract

This invention discloses a multi-state magnetic random access memory (MRRAM), comprising a bottom electrode with a first current channel and a second current channel that are perpendicular to each other and electrically isolated; a cylindrical giant magnetoresistive / tunneling magnetoresistive structure disposed on the bottom electrode; a top electrode disposed on the giant magnetoresistive / tunneling magnetoresistive structure; and a spin generation layer disposed on a cross-shaped electrode, receiving current from the two channels to generate spin orbit moments. This invention, through dual-current synthesized spin orbit moment technology, achieves precise multi-angle control of the magnetic moment direction of the ferromagnetic layer while ensuring complete flipping of the antiferromagnetic layer (high stability); it resolves the contradiction between stability and multi-stateness, enabling the MRRAM to store multiple stable resistive states while maintaining high stability, significantly improving storage density.

Description

Technical Field

[0001] This invention relates to the field of data storage technology, and in particular to a multi-state magnetic random access memory. Background Technology

[0002] With the explosive growth of fields such as artificial intelligence, neural networks, and the Internet of Things, data storage technology is facing unprecedented challenges and opportunities. Traditional binary storage technology, which can only store data using two values, "0" and "1", is no longer able to meet the current urgent needs for high storage density, high read / write speed, long cycle life, low power consumption, and non-volatile storage solutions.

[0003] Against this backdrop, multi-resistivity magnetic random access memory (MRRAM) technology has emerged and gradually become a research hotspot. MRRAM technology stores multiple values ​​in a single memory cell, significantly improving storage density while offering advantages such as low energy consumption and low cost. This technology is primarily based on giant magnetoresistance (GMR) or tunneling magnetoresistance (TMR) structures, achieving the storage of different resistance states by controlling the magnetization states of the free layer and the reference layer.

[0004] In recent years, the spin-orbit moment (SOT) effect has provided a new approach to achieving multi-state magnetic storage. Existing multi-state storage technologies based on the SOT effect mainly adjust the degree of antiferromagnetic order reversal in the antiferromagnetic pinning layer by controlling the magnitude of a single current, thereby affecting the number, size, and orientation of ferromagnetic orders in the free / reference layer to achieve four or more stable resistance states. However, this technology has the following drawbacks: First, insufficient multi-state stability. Existing technologies achieve multi-state control by controlling partial reversal of the antiferromagnetic order, but the pinning strength corresponding to different degrees of reversal varies significantly. Theoretical analysis and experimental results show that the pinning effect is strongest only when the antiferromagnetic order is completely reversed, resulting in optimal device thermal stability and anti-interference capability; while the pinning strength is weaker in the partially reversed state, making the device susceptible to temperature fluctuations, external magnetic field interference, and other factors, leading to resistance state drift or even information loss.

[0005] Second, the precision of magnetic moment angle control is limited. Single-current control methods cannot achieve continuous or quasi-continuous precise control of the magnetic moment angle within the 0-360° range. Because the degree of antiferromagnetic sequence reversal is non-linearly related to the current magnitude, and there are reversal thresholds and hysteresis effects, the writing window for the intermediate resistive state is narrow and repeatability is poor.

[0006] Third, write operations have low reliability. In the single-current scheme, different resistance states correspond to different critical switching currents. Write operations require precise control of the current pulse amplitude, which places stringent requirements on circuit design. At the same time, the relaxation time of some switching states is relatively short, raising concerns about long-term data retention.

[0007] In summary, existing multi-state magnetic random access memory (MRAM) technologies based on the SOT effect face a core contradiction: achieving both stability and controllability is difficult. Pursuing complete flipping for high stability necessitates two-state storage; pursuing multi-state storage requires accepting stability losses due to partial flipping. Therefore, achieving precise multi-angle control of the magnetic moment direction to obtain multiple stable resistive states while ensuring complete flipping (high stability) has become a critical technical problem urgently needing to be solved in the field of multi-state MRAMs. Summary of the Invention

[0008] This invention provides a polymorphic magnetic random access memory (MRRAM) designed to solve the technical problem of how to achieve stable and precisely controlled complete flipping in a polymorphic MRRAM.

[0009] In view of the above technical problems, embodiments of the present invention provide a multi-state magnetic random access memory, comprising:

[0010] The bottom electrode includes a first current channel and a second current channel, wherein the first current channel and the second current channel are perpendicular to each other and electrically isolated;

[0011] A giant magnetoresistive / tunneling magnetoresistive structure, having a cylindrical structure, is disposed on the bottom electrode;

[0012] The top electrode is disposed on the giant magnetoresistive / tunneling magnetoresistive structure;

[0013] When the bottom electrode is a cross-shaped structure, the top electrode is a long strip shape; or when the bottom electrode is a long strip shape, the top electrode is a cross-shaped structure.

[0014] A spin generation layer is disposed on an electrode having a cross-shaped structure. The spin generation layer is used to receive current from the first current channel and the second current channel and generate spin orbital moments.

[0015] Specifically, by controlling the current direction and current density of the first current channel and the second current channel respectively, synthesizing spin orbit moments in different directions, the magnetic moment direction of the spin generation layer can achieve multi-angle stable deflection within the range of 0-360°, thereby realizing multi-state storage.

[0016] Optionally, when the bottom electrode is a cross-shaped structure and the top electrode is a strip-shaped structure; the bottom electrode includes a substrate, a seed layer, an antiferromagnetic layer, and a free layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure includes a capping layer, a reference layer, and a spacer layer arranged sequentially from top to bottom; or

[0017] A portion of the free layer is incorporated into the bottom electrode, and another portion of the free layer is incorporated into the giant magnetoresistance / tunneling magnetoresistance structure; wherein the antiferromagnetic layer serves as the spin-generating layer.

[0018] Optionally, when the bottom electrode is a cross-shaped structure and the top electrode is a strip-shaped structure; the bottom electrode includes a substrate, a seed layer, an antiferromagnetic layer, and a reference layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure includes a capping layer, a free layer, and a spacer layer arranged sequentially from top to bottom; or

[0019] A portion of the reference layer is disposed within the bottom electrode, and another portion of the reference layer is disposed within the giant magnetoresistance / tunneling magnetoresistance structure; wherein the antiferromagnetic layer serves as the spin-generating layer.

[0020] Optionally, when the bottom electrode is an elongated structure and the top electrode is a cross-shaped structure; the bottom electrode includes a substrate, a seed layer, and a reference layer arranged sequentially from bottom to top; the giant magnetoresistive / tunneling magnetoresistive structure includes an antiferromagnetic layer, a free layer, and a spacer layer arranged sequentially from top to bottom; the top electrode includes a track reinforcement layer; or

[0021] A portion of the reference layer is disposed within the bottom electrode, and another portion of the reference layer is disposed within the giant magnetoresistance / tunneling magnetoresistance structure; wherein the antiferromagnetic layer serves as the spin-generating layer.

[0022] Optionally, when the bottom electrode is an elongated strip structure and the top electrode is a cross-shaped structure; the bottom electrode includes a substrate, a seed layer, and a free layer arranged sequentially from bottom to top; the giant magnetoresistive / tunneling magnetoresistive structure includes an antiferromagnetic layer, a reference layer, and a spacer layer arranged sequentially from top to bottom; the top electrode includes a track reinforcement layer; or

[0023] A portion of the free layer is incorporated into the bottom electrode, and another portion of the free layer is incorporated into the giant magnetoresistance / tunneling magnetoresistance structure; wherein the antiferromagnetic layer serves as the spin-generating layer.

[0024] Optionally, the spin-generating layer further includes an orbital enhancement layer, which is a transition metal layer composed of one or more metals selected from Pt, Ta, Ru, and Zr.

[0025] Optionally, the material of the antiferromagnetic material layer is IrMn, PtMn, or Ir x Mn 1-x Pt x Mn 1-x Pd x Mn 1-xOne of NiO, wherein the thickness of the antiferromagnetic material layer is 3nm-20nm.

[0026] Optionally, the free layer is a multi-element alloy layer composed of two or more elements selected from Co, Fe, Ni, Cr, V, Mn, C, and B; the seed layer is composed of one or more materials selected from Ta, Ru, NiCr, and NiFeCr.

[0027] Optionally, the reference layer is one or more of the single-layer ferromagnetic metals Co, CoFe, and CoFeB with high coercivity, or it is a composite structure of a ferromagnetic layer and an antiferromagnetic layer, or a composite structure of an artificially synthesized antiferromagnetic structure and an antiferromagnetic layer.

[0028] Optionally, the spacer layer is MgO, Al2O3, HfO2, MgAl2O4, or CuO. x One or more components of Cu materials.

[0029] This invention fundamentally overcomes the core contradiction of the incompatibility between stability and polymorphism in existing technologies through a dual-current vector synthesis mechanism. The invention employs a cross-shaped electrode structure to introduce orthogonal dual currents, utilizing the vector superposition of the SOT effect to ensure the antiferromagnetic sequence is always in a fully flipped state, with a constant maximum pinning strength. While ensuring high stability, it achieves precise multi-angle control of the magnetic moment within the 0-360° range. Each resistive state has the same thermal stability barrier, significantly extending data retention time. Due to the complete flipping of the antiferromagnetic layer, the polymorphic magnetic random access memory in this invention exhibits stronger anti-interference capabilities and thermal stability. Under conditions of temperature fluctuations or external magnetic field interference, the device can maintain a stable resistive state, effectively preventing resistive state drift and information loss, and improving the reliability of data storage.

[0030] This invention achieves linear and precise control of the magnetic moment angle and significantly improves write reliability. In existing technologies, the magnetic moment angle exhibits a non-linear relationship with current, and is affected by the flip threshold and hysteresis effects, resulting in a narrow write window for the intermediate resistive state. By controlling the ratio of the two current densities, linear control of the magnetic moment angle is achieved, transforming the write operation from "absolute amplitude control" to "relative ratio control." This significantly reduces the dependence on the accuracy of the current source, allowing the circuit design to utilize a mature differential drive architecture. The write window is wide, repeatability is good, and the practical reliability of polymorphic storage is significantly improved. Furthermore, the dual-current synthesized spin-orbit moment technology simplifies circuit design, reduces the requirement for precise control of the current pulse amplitude, and improves circuit stability and reliability. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the overall structure of a multi-state magnetic random access memory in one embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram illustrating the working principle of dual-current combined spin orbital moment in one embodiment of the present invention;

[0034] Figure 3 This is a schematic cross-sectional view of the device structure according to Embodiment 1 of the present invention;

[0035] Figure 4 This is a schematic cross-sectional view of the device structure according to Embodiment 2 of the present invention;

[0036] Figure 5 This is a schematic cross-sectional view of the device structure in Embodiment 3 of the present invention;

[0037] Figure 6 This is a schematic cross-sectional view of the device structure in Embodiment 4 of the present invention.

[0038] The reference numerals in the accompanying drawings are as follows:

[0039] 1-Bottom electrode, 11-First current channel, 12-Second current channel, 2-Spin generation layer, 3-Giant magnetoresistance / tunneling magnetoresistance structure, 4-Top electrode. Detailed Implementation

[0040] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0041] like Figures 1 to 6 As shown, one embodiment of the present invention provides a multi-state magnetic random access memory, comprising:

[0042] The bottom electrode 1 includes a first current channel 11 and a second current channel 12, wherein the first current channel 11 and the second current channel 12 are perpendicular to each other and electrically isolated.

[0043] The giant magnetoresistive / tunneling magnetoresistive structure 3 has a cylindrical structure and is disposed on the bottom electrode 1;

[0044] The top electrode 4 is disposed on the giant magnetoresistive / tunneling magnetoresistive structure 3;

[0045] When the bottom electrode 1 has a cross-shaped structure, the top electrode 4 has a long strip shape; or when the bottom electrode 1 has a long strip shape, the top electrode 4 has a cross-shaped structure.

[0046] Spin generating layer 2 is disposed on an electrode having a cross-shaped structure. The spin generating layer 2 is used to receive current from the first current channel 11 and the second current channel 12 and generate spin orbital moments.

[0047] Specifically, by controlling the current direction and current density of the first current channel 11 and the second current channel 12 respectively, synthesized spin orbit moments in different directions are generated, so that the magnetic moment direction of the spin generation layer 2 can achieve multi-angle stable deflection within the range of 0-360°, thereby realizing multi-state storage.

[0048] Understandably, such as Figure 2 As shown, this invention utilizes a dual current vector synthesis mechanism to achieve precise angular control of the ferromagnetic layer's magnetic moment within the 0-360° range through the superposition of spin-orbit torques (SOTs) generated by orthogonal current channels. This allows for the acquisition of multiple stable resistive states within a single memory cell, thus resolving the core contradiction in existing technologies where stability and controllability are difficult to achieve simultaneously. Specifically, its principle can be explained from the following aspects:

[0049] Firstly, the generation mechanism of spin orbital moment (SOT) lies in the fact that SOT is the torque effect generated by the conversion of charge current into spin polarization current under spin-orbit coupling, mainly including three physical mechanisms:

[0050] The spin Hall effect (SHE) occurs in materials with strong spin-orbit coupling (such as heavy metals Pt and Ta). When an electric current passes through these materials, spin-up electrons and spin-down electrons are subjected to forces in opposite directions, generating a spin-polarized current perpendicular to the current direction.

[0051] The Rashba-Edelstein effect occurs at interfaces with broken structural inversion symmetry (such as ferromagnetic / heavy metal interfaces). Due to the electric field gradient, an equivalent magnetic field is generated, which polarizes the electron spin. This effect is particularly significant at antiferromagnetic / ferromagnetic interfaces.

[0052] The Orbital Hall effect (OHE) occurs when, under the influence of an applied electric field, the orbital angular momentum of electrons is transported laterally in a direction perpendicular to the current. Electrons with different orbital angular motive forces deflect in opposite directions, creating a net orbital current. This current is converted into a spin current when passing through materials with strong spin-orbit coupling or within ferromagnetic metals, generating a torque.

[0053] This invention is based on the spin orbital moment (SOT) effect, and the expression for the torque generated by the spin orbital moment (SOT) effect is as follows:

[0054]

[0055] Where φ represents the spin Hall angle, Indicates spin-orbit torque. Indicates the SOT current density. This represents the conversion efficiency coefficient. , Indicates the direction vector of magnetic moment. Represents the spin polarization vector. Indicates the gyromagnetic ratio, Denotes Planck's constant. Indicates the amount of electron charge. Indicates saturation magnetization. Indicates the thickness of the magnetic layer.

[0056] As can be seen from the above torque expression, the torque generated by the SOT effect is closely related to factors such as the SOT current density. Furthermore, the relationship between the torque generated by the SOT effect and the current is as follows:

[0057]

[0058] This indicates that the equivalent magnetic field can be affected by controlling the SOT current, thereby influencing the magnetic moment.

[0059] This invention employs a dual-current pulse control mechanism, simultaneously introducing two orthogonal pulse currents into the spin generation layer 2 (a cross-shaped electrode structure), forming two mutually perpendicular and electrically isolated current channels. The first current channel 11 (X-direction): a current density J is introduced along the X-axis direction. X Second current channel 12 (Y direction): Current density J is passed through it along the Y-axis. Y Specifically, a pulsed current in the X direction can generate an effective field in the Y direction, and a pulsed current in the Y direction can generate an effective field in the X direction. This characteristic of the effective field generated by orthogonal currents is the key foundation for achieving precise control of the magnetic moment. When a pulsed current is applied, if the current exceeds a certain threshold, the uncompensated magnetic moment at the antiferromagnetic / ferromagnetic layer interface will be precisely adjusted to a certain angle, thereby fixing the magnetic moment of the adjacent ferromagnetic layer at this angle. By changing the magnitudes of the two current densities, the angle generated by the magnetic moment of the antiferromagnetic / ferromagnetic layer can be precisely controlled, and the angular relationship satisfies: ;in, This represents the current density in the X direction. This represents the current density in the Y direction. Based on a giant magnetoresistance (GMR) or tunneling magnetoresistance (TMR) structure, it represents the angle between the device resistance and the relative magnetic moments of the free layer and the reference layer. The following relationship must be satisfied:

[0060]

[0061] in, Indicates the angle between magnetic moments. This represents the resistance value in the parallel state. This represents the resistance value under antiparallel conditions. This indicates the resistance value. Because the angle between one layer of magnetic moment and the coordinate axis can be precisely controlled through dual current pulse modulation. This leads to a change in the angle α between the reference layer and the free layer, resulting in different... The value will correspond to different resistance values. In the storage cell, each specific resistance value This can represent a storage state. Therefore, by fixing one of the reference layers or the free layers, the magnetic moment angle of the other layer can be precisely controlled. This allows the storage cell to exhibit multiple different stable resistance states, thereby enabling a single physical storage cell to directly store multiple resistance states, significantly improving storage density.

[0062] In practical operation, pulsed currents of specific magnitude and direction in the X and Y directions are simultaneously applied to the spin generation layer. The torque generated by the SOT effect acts on the magnetic moment, thereby achieving precise control of the magnetic moment angle. This ensures the magnetic moment reaches the desired angle, forming a corresponding resistance state to store information. During reading, the resistance value of the storage cell is measured, and the magnetic moment angle is deduced from the magnetoresistance formula, thus determining the stored information. This not only achieves multi-state storage and improves storage density but also offers advantages such as low energy consumption and fast read / write speeds due to the precise control of the magnetic moment based on current. Therefore, this invention employs a cross-shaped electrode structure to introduce a dual-current-channel design. Utilizing the vector superposition characteristics of the SOT effect, it achieves precise multi-angle control of the magnetic moment direction of the ferromagnetic layer while ensuring complete flipping of the antiferromagnetic layer (high stability), fundamentally resolving the contradiction between stability and multi-stateness in existing technologies.

[0063] In one embodiment, such as Figure 3 As shown, when the bottom electrode 1 has a cross-shaped structure and the top electrode 4 has a long strip-shaped structure; the bottom electrode 1 includes a substrate, a seed layer, an antiferromagnetic layer and a free layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure 3 includes a cover layer, a reference layer and a spacer layer arranged sequentially from top to bottom, wherein the antiferromagnetic layer serves as the spin generation layer 2.

[0064] Furthermore, in another embodiment, a portion of the free layer is configured into the bottom electrode 1, and another portion of the free layer is configured into the giant magnetoresistance / tunneling magnetoresistance structure 3; wherein the antiferromagnetic layer serves as the spin-generating layer 2.

[0065] In one embodiment, such as Figure 4 As shown, when the bottom electrode 1 has a cross-shaped structure and the top electrode 4 has a long strip-shaped structure; the bottom electrode 1 includes a substrate, a seed layer, an antiferromagnetic layer and a reference layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure 3 includes a cover layer, a free layer and a spacer layer arranged sequentially from top to bottom, wherein the antiferromagnetic layer serves as the spin generation layer 2.

[0066] Furthermore, in another embodiment, a portion of the reference layer is disposed in the bottom electrode 1, and another portion of the reference layer is disposed in the giant magnetoresistance / tunneling magnetoresistance structure 3; wherein the antiferromagnetic layer serves as the spin-generating layer 2.

[0067] In one embodiment, such as Figure 5 As shown, when the bottom electrode 1 is a long strip-shaped structure and the top electrode 4 is a cross-shaped structure; the bottom electrode 1 includes a substrate, a seed layer and a reference layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure 3 includes an antiferromagnetic layer, a free layer and a spacer layer arranged sequentially from top to bottom; the top electrode 4 includes an orbital enhancement layer, wherein the antiferromagnetic layer serves as the spin generation layer 2.

[0068] Furthermore, in another embodiment, a portion of the reference layer is disposed in the bottom electrode 1, and another portion of the reference layer is disposed in the giant magnetoresistance / tunneling magnetoresistance structure 3; wherein the antiferromagnetic layer serves as the spin-generating layer 2.

[0069] In one embodiment, such as Figure 6 As shown, when the bottom electrode 1 is a long strip structure and the top electrode 4 is a cross-shaped structure; the bottom electrode 1 includes a substrate, a seed layer and a free layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure 3 includes an antiferromagnetic layer, a reference layer and a spacer layer arranged sequentially from top to bottom; the top electrode 4 includes an orbital enhancement layer, wherein the antiferromagnetic layer serves as the spin generation layer 2.

[0070] Furthermore, in another embodiment, a portion of the free layer is configured into the bottom electrode 1, and another portion of the free layer is configured into the giant magnetoresistance / tunneling magnetoresistance structure 3; wherein the antiferromagnetic layer serves as the spin-generating layer 2.

[0071] In one embodiment, the spin generation layer 2 further includes an orbital enhancement layer, which is a transition metal layer, including but not limited to one or more metals selected from Pt, Ta, Ru, and Zr.

[0072] In one embodiment, the material of the antiferromagnetic material layer includes, but is not limited to, IrMn, PtMn, and Ir x Mn 1-x Pt x Mn 1-x Pd x Mn 1-x One of NiO, wherein the thickness of the antiferromagnetic material layer is 3nm-20nm.

[0073] In one embodiment, the free layer is a multi-element alloy layer composed of two or more elements selected from Co, Fe, Ni, Cr, V, Mn, C, and B, including but not limited to the aforementioned element types; the seed layer is composed of one or more materials selected from Ta, Ru, NiCr, and NiFeCr, including but not limited to the aforementioned material types.

[0074] In one embodiment, the reference layer is one or more of the single-layer ferromagnetic metals Co, CoFe, and CoFeB with high coercivity, including but not limited to the above-mentioned metal types, or a composite structure of a ferromagnetic layer and an antiferromagnetic layer (such as CoFeB / PtMn), or a composite structure of an artificially synthesized antiferromagnetic structure and an antiferromagnetic layer (such as CoFeB / Ru / CoFe / PtMn).

[0075] In one embodiment, the spacer layer is MgO, Al2O3, HfO2, MgAl2O4, or CuO. x One or more of the following materials: Cu, including but not limited to the types of materials mentioned above.

[0076] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A multi-state magnetic random access memory, characterized in that, include: The bottom electrode (1) includes a first current channel (11) and a second current channel (12), wherein the first current channel (11) and the second current channel (12) are perpendicular to each other and electrically isolated; The giant magnetoresistive / tunneling magnetoresistive structure (3) has a cylindrical structure and is disposed on the bottom electrode (1); The top electrode (4) is disposed on the giant magnetoresistance / tunneling magnetoresistance structure (3); When the bottom electrode (1) is a cross-shaped structure, the top electrode (4) is a long strip-shaped structure; or when the bottom electrode (1) is a long strip-shaped structure, the top electrode (4) is a cross-shaped structure. A spin generation layer (2) is disposed on an electrode having a cross-shaped structure. The spin generation layer (2) is used to receive current from the first current channel (11) and the second current channel (12) and generate a spin orbital moment. In this process, by controlling the current direction and current density of the first current channel (11) and the second current channel (12) respectively, synthesizing spin orbit moments in different directions, the magnetic moment direction of the spin generation layer (2) can achieve multi-angle stable deflection within the range of 0-360°, thereby realizing multi-state storage.

2. The multi-state magnetic random access memory according to claim 1, characterized in that, When the bottom electrode (1) is a cross-shaped structure and the top electrode (4) is a long strip-shaped structure; the bottom electrode (1) includes a substrate, a seed layer, an antiferromagnetic layer and a free layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure (3) includes a capping layer, a reference layer and a spacer layer arranged sequentially from top to bottom; or A portion of the free layer is configured into the bottom electrode (1), and another portion of the free layer is configured into the giant magnetoresistance / tunneling magnetoresistance structure (3); wherein the antiferromagnetic layer serves as the spin-generating layer (2).

3. The multi-state magnetic random access memory according to claim 1, characterized in that, When the bottom electrode (1) is a cross-shaped structure and the top electrode (4) is a strip-shaped structure; the bottom electrode (1) includes a substrate, a seed layer, an antiferromagnetic layer and a reference layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure (3) includes a cover layer, a free layer and a spacer layer arranged sequentially from top to bottom; or A portion of the reference layer is disposed in the bottom electrode (1), and another portion of the reference layer is disposed in the giant magnetoresistance / tunneling magnetoresistance structure (3); wherein the antiferromagnetic layer serves as the spin-generating layer (2).

4. The multi-state magnetic random access memory according to claim 1, characterized in that, When the bottom electrode (1) is a long strip structure and the top electrode (4) is a cross-shaped structure; the bottom electrode (1) includes a substrate, a seed layer and a reference layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure (3) includes an antiferromagnetic layer, a free layer and a spacer layer arranged sequentially from top to bottom; the top electrode (4) includes a track reinforcement layer; or A portion of the reference layer is disposed in the bottom electrode (1), and another portion of the reference layer is disposed in the giant magnetoresistance / tunneling magnetoresistance structure (3); wherein the antiferromagnetic layer serves as the spin-generating layer (2).

5. The multi-state magnetic random access memory according to claim 4, characterized in that, When the bottom electrode (1) is a long strip structure and the top electrode (4) is a cross-shaped structure; the bottom electrode (1) includes a substrate, a seed layer and a free layer arranged sequentially from bottom to top; the giant magnetoresistance / tunneling magnetoresistance structure (3) includes an antiferromagnetic layer, a reference layer and a spacer layer arranged sequentially from top to bottom; the top electrode (4) includes a track reinforcement layer; or A portion of the free layer is configured into the bottom electrode (1), and another portion of the free layer is configured into the giant magnetoresistance / tunneling magnetoresistance structure (3); wherein the antiferromagnetic layer serves as the spin-generating layer (2).

6. The multi-state magnetic random access memory according to any one of claims 2-3, characterized in that, The spin generation layer (2) further includes an orbital enhancement layer, which is a transition metal layer composed of one or more of Pt, Ta, Ru, and Zr metals.

7. The multi-state magnetic random access memory according to any one of claims 2-5, characterized in that, The antiferromagnetic material layer is made of IrMn, PtMn, or Ir. x Mn 1-x Pt x Mn 1-x Pd x Mn 1-x One of NiO, wherein the thickness of the antiferromagnetic material layer is 3nm-20nm.

8. The multi-state magnetic random access memory according to claim 7, characterized in that, The free layer is a multi-element alloy layer composed of two or more elements selected from Co, Fe, Ni, Cr, V, Mn, C, and B; the seed layer is composed of one or more materials selected from Ta, Ru, NiCr, and NiFeCr.

9. The multi-state magnetic random access memory according to claim 8, characterized in that, The reference layer is one or more of the single-layer ferromagnetic metals Co, CoFe, and CoFeB with high coercivity, or a composite structure of a ferromagnetic layer and an antiferromagnetic layer, or a composite structure of an artificially synthesized antiferromagnetic structure and an antiferromagnetic layer.

10. The multi-state magnetic random access memory according to claim 9, characterized in that, The spacer layer is composed of MgO, Al2O3, HfO2, MgAl2O4, and CuO. x One or more components of Cu materials.

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