Magnetic memory device and method of storing information

Abstract

The application provides a magnetic storage device and a storage information method, the storage information method comprising: generating an exchange bias field through exchange coupling between an antiferromagnetic layer and a ferromagnetic free layer; enhancing thermal stability of a perpendicular magnetic moment through the exchange bias field; wherein the perpendicular magnetic moment is a carrier of information storage; applying an external charge current to the antiferromagnetic layer to generate an out-of-plane spin polarization current; and flipping the perpendicular magnetic moment through the out-of-plane spin polarization current to store information. The application can greatly improve thermal stability and writing efficiency of the magnetic storage device, simplify the magnetization flipping process, reduce system complexity and power consumption, and provide technical support for development of a next-generation high-density, low-power magnetic storage device.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of magnetic storage, in particular to a spin orbit torque (SOT) magnetic storage device, and specifically to a magnetic storage device and a method for storing information. BACKGROUND

[0002] Magnetic tunnel junctions composed of a ferromagnetic layer with perpendicular anisotropy have great prospects in realizing high-density non-volatile storage and logic. And related research has shown that the magnetic tunnel junction flip introduced by current has the advantages of high speed and low power consumption. However, there are still two important problems to be solved if we want to realize high-density magnetic storage based on magnetic tunnel junctions:

[0003] 1. The thermal stability of the magnetic nanometer junction needs to be improved. If we want to store information in a high-density magnetic storage for more than 10 years, the thermal stability parameter defined by the ratio of magnetic anisotropy EM to thermal energy Kt should exceed 60. However, as the size of the magnetic storage device shrinks to sub-ten nanometers, the perpendicular magnetic anisotropy is significantly weakened, making it difficult to achieve stable magnetic storage at room temperature.

[0004] 2. Deterministic flip without external field assistance needs to be realized. SOT flip of the perpendicular magnetic moment usually requires the application of an in-plane magnetic field assistance, which increases the system complexity and power consumption, and limits the integration and application of the device. SUMMARY

[0005] The present application provides a magnetic storage device and a method for storing information, aiming to solve the technical problems existing in the prior art spin orbit torque magnetic storage device, especially the problems of insufficient thermal stability and the need for in-plane magnetic field assistance for magnetization flip when the SOT device based on the perpendicular magnetic moment is shrunk to sub-ten nanometer size.

[0006] In order to solve at least one of the above problems existing in the prior art, in a first aspect, the embodiments of the present application provide a magnetic storage device, comprising:

[0007] a ferromagnetic reference layer;

[0008] a tunneling layer, one side of which is arranged in close contact with the ferromagnetic reference layer;

[0009] a ferromagnetic free layer, one side of which is arranged in close contact with the other side of the tunneling layer;

[0010] an antiferromagnetic layer, which is arranged in close contact with the other side of the ferromagnetic free layer, and is made of a non-mirror-symmetric antiferromagnetic material.

[0011] In some embodiments of the present application, the antiferromagnetic layer has spin orbit coupling properties.

[0012] In some embodiments of the present application, the carrier of information storage is a perpendicular magnetic moment.

[0013] In a second aspect, embodiments of the present application provide a method for storing information in the magnetic memory device, comprising:

[0014] generating an exchange bias field through exchange coupling between the antiferromagnetic layer and the ferromagnetic free layer;

[0015] enhancing thermal stability of the perpendicular magnetic moment through the exchange bias field; wherein the perpendicular magnetic moment is a carrier of information storage;

[0016] applying an external charge current to the antiferromagnetic layer to generate an out-of-plane spin-polarized current;

[0017] reversing the perpendicular magnetic moment through the out-of-plane spin-polarized current to store information.

[0018] In some embodiments of the present application, reversing the perpendicular magnetic moment through the out-of-plane spin-polarized current comprises:

[0019] generating a spin-orbit torque in the ferromagnetic free layer through the out-of-plane spin-polarized current;

[0020] reversing the perpendicular magnetic moment through the spin-orbit torque.

[0021] In some embodiments of the present application, a method for storing information further comprises:

[0022] making the energy of the ferromagnetic free layer in +z direction different from that in -z direction through different exchange bias fields to generate different magnetic ground states.

[0023] In some embodiments of the present application, a method for storing information further comprises:

[0024] reversing the perpendicular magnetic moment through the different magnetic ground states and the spin-orbit torque.

[0025] In some embodiments of the present application, the direction of the external charge current, the polarization direction of the out-of-plane spin-polarized current and the direction of the exchange bias field are in one-to-one correspondence.

[0026] In some embodiments of the present application, a method for storing information further comprises:

[0027] controlling the direction of the external charge current to make the perpendicular magnetic moment reverses deterministically.

[0028] In some embodiments of the present application, controlling the direction of the external charge current to make the perpendicular magnetic moment reverses deterministically comprises:

[0029] The polarization direction of the out-of-plane spin polarization current is changed by controlling the direction of the additional charge current;

[0030] The exchange bias field is changed by controlling the polarization direction of the out-of-plane spin polarization current;

[0031] The vertical magnetic moment is deterministically flipped by controlling the exchange bias field.

[0032] Firstly, from the above description, the magnetic storage device provided by the embodiment of the application comprises: a ferromagnetic reference layer; a tunneling layer, one side of which is arranged in abutment with the ferromagnetic reference layer; a ferromagnetic free layer, one side of which is arranged in abutment with the other side of the tunneling layer; and an anti-ferromagnetic layer, which is arranged in abutment with the other side of the ferromagnetic free layer, and is made of an anti-ferromagnetic material which is not mirror-symmetrical.

[0033] Secondly, the embodiment of the application further provides a method for storing information by using the above magnetic storage device, which comprises the following steps: firstly, generating an exchange bias field through the exchange coupling effect between the anti-ferromagnetic layer and the ferromagnetic free layer; enhancing the thermal stability of a vertical magnetic moment through the exchange bias field; wherein the vertical magnetic moment is a carrier of information storage; then, applying an additional charge current to the anti-ferromagnetic layer to generate an out-of-plane spin polarization current; and finally, flipping the vertical magnetic moment through the out-of-plane spin polarization current to store information.

[0034] To sum up, the application provides a novel magnetic storage device based on an exchange bias field and an out-of-plane spin-orbit torque current, which can greatly improve the thermal stability and writing efficiency of the magnetic storage device, simplify the magnetization flipping process, and reduce the system complexity and power consumption, thereby providing technical support for the development of the next generation of high-density and low-power magnetic storage devices. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor. In the drawings:

[0036] Figure 1 Schematic diagram of the exchange bias field and the out-of-plane spin current regulating the magnetic tunnel junction of the magnetic storage device Figure 1 .

[0037] Figure 2 Schematic diagram of the exchange bias field and the out-of-plane spin current regulating the magnetic tunnel junction of the magnetic storage device Figure 2 .

[0038] Figure 3A schematic diagram of a magnetic tunnel structure of a magnetic storage device in the prior art.

[0039] Figure 4 A flowchart of a method for storing information using the magnetic storage device according to an embodiment of the present application Figure 1 .

[0040] Figure 5 A flowchart of step 400 according to an embodiment of the present application.

[0041] Figure 6 A flowchart of step 800 according to an embodiment of the present application.

[0042] Figure 7 A schematic diagram of the principle of exchange bias field improving thermal stability and auxiliary deterministic magnetization switching according to an embodiment of the present application Figure 1 .

[0043] Figure 8 A schematic diagram of the principle of exchange bias field improving thermal stability and auxiliary deterministic magnetization switching according to an embodiment of the present application Figure 2 .

[0044] Figure 9 A schematic diagram of the principle of exchange bias field improving thermal stability and auxiliary deterministic magnetization switching according to an embodiment of the present application Figure 3 .

[0045] The drawings are schematic diagrams, wherein the thickness of each functional layer or region involved is not an actual size, and the distance between functional regions is not an actual value. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0047] It should be noted that the terms “comprising” and “having” and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover not exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to the process, method, product or device. The embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0048] Detailed examples are disclosed herein, and the specific structural and functional details are for illustrative purposes only. Therefore, the invention may be practiced in many alternative forms, and the invention should not be construed as being limited to the exemplary embodiments set forth herein, but should cover all variations, equivalents and alternatives falling within the scope of the invention.

[0049] Spintronics, an emerging branch of electronics, utilizes the spin degree of freedom of electrons to process information. Compared to traditional charge-based electronics, it offers advantages such as lower power consumption, higher speed, and non-volatility. Particularly in the field of memory, spin memory devices offer higher speed, lower power consumption, and non-volatility compared to traditional charge-based memory devices.

[0050] Magnetic Random Access Memory (MRAM) has become a major application area in spin memory devices. After years of development, its information writing method has formed three types of MRAM, including Toggle-MRAM based on magnetic field writing, STT-MRAM based on spin-transfer torque (STT) writing, and SOT-MRAM based on spin-orbit torque (SOT) writing.

[0051] Toggle-MRAM uses an external magnetic field to flip the magnetization direction of the free layer in the memory cell, thereby enabling data writing. Toggle-MRAM cells offer high stability and durability, making them suitable for applications requiring long-term reliability. However, relying on an external magnetic field for writing results in high power consumption and slow write speeds. The need for complex magnetic field control also limits integration and scalability. STT-MRAM utilizes the spin-orbit moment effect, applying current to bias electron spins, thus flipping the magnetization direction of the free layer. Compared to Toggle-MRAM, STT-MRAM does not require an external magnetic field, reducing system complexity and power consumption. Simultaneously, STT-MRAM offers faster write speeds and better scalability. However, as the cell size shrinks, the write current requirement of STT increases significantly, leading to increased power consumption. Furthermore, the randomness of writing and the long write latency can affect data reliability. SOT-MRAM achieves magnetization reversal through the spin-orbit moment effect. By applying current to generate a spin current in the heavy metal layer, a spin-orbit moment effect is induced in the free layer, achieving magnetic moment reversal. SOT-MRAM offers extremely fast write speeds, higher efficiency, and lower write current. Furthermore, it enables high-frequency operation without requiring read / write separation and exhibits excellent durability.

[0052] However, the three kinds of magnetic random access memory have the following technical problems: as the magnetic memory device size is reduced to sub-10 nanometers, the perpendicular magnetic anisotropy is significantly weakened, and it is difficult to achieve stable magnetic storage at room temperature. In addition, the three kinds of magnetic random access memory all need to realize deterministic flipping without external field assistance, which increases the system complexity and power consumption, and limits the integration and application of the device.

[0053] Based on this, the embodiment of the present application provides a magnetic memory device. Figure 1 A schematic diagram of the magnetic memory device of the embodiment of the present application is shown in FIG. 1. Figure 1 and Figure 2 As shown in is the spin current of out-of-plane (z direction) polarization, is the exchange bias field, and I is the applied external charge current. The magnetic memory device comprises:

[0054] a ferromagnetic reference layer 1;

[0055] a tunneling layer 2, one side of which is arranged in abutment with the ferromagnetic reference layer 1;

[0056] a ferromagnetic free layer 3, one side of which is arranged in abutment with the other side of the tunneling layer 2;

[0057] an antiferromagnetic layer 4, which is arranged in abutment with the other side of the ferromagnetic free layer 3, and is made of a non-mirror-symmetrical antiferromagnetic material.

[0058] Referring to Figure 3 which shows a magnetic memory of the prior art, and the difference between the magnetic memory of the prior art and the magnetic memory provided by the present application is that the bottom of the magnetic memory of the prior art is heavy metal material 5, while the corresponding thin layer of the present application is an antiferromagnetic layer.

[0059] Continuing to refer to Figure 3 a schematic diagram of the magnetic tunnel structure of the magnetic memory device of the prior art, Figure 3 in which is the spin current of in-plane (y direction) polarization, For the magnetic field in the x direction, I is the applied charge current, the in-plane spin-polarized current in the prior art works with the help of the external magnetic field, in the tunnel junction, the magnetic anisotropy energy is rapidly reduced due to the size reduction, and stable storage cannot be realized in the sub-ten nanometer case. Due to the spin Hall effect, the current flowing through the heavy metal layer is converted into a spin-polarized current, but due to the high symmetry restriction, it can only generate an in-plane spin-polarized current to act on the magnetic moment, and can be transmitted to the ferromagnetic free layer to make the magnetic moment in the plane; if you want to realize the determined flip in the vertical direction, you also need to assist with the external in-plane magnetic field. It can be understood that the introduction of the external magnetic field greatly increases the difficulty of power consumption reduction and size miniaturization. Generally, the material for generating in-plane spin-polarized current in the magnetic storage device is heavy metal, such as platinum (Pt), iridium (Ir) and the like.

[0060] In contrast, the present application proposes a kind of high-performance magnetic storage device using anti-ferromagnetic layer with symmetry breaking (non-mirror symmetry) to replace the heavy metal layer in the prior art to generate in-plane spin current, to realize full electrical control. The out-of-plane spin-polarized current generated by the anti-ferromagnetic layer can directly act on the vertical magnetic moment of the ferromagnetic free layer, and the exchange coupling effect formed between it and the ferromagnetic free layer generates an exchange bias field to improve the thermal stability of the vertical magnetic moment, and the applied charge current can directly control the exchange bias field. The direction of the applied charge current, the polarization direction of the vertical spin-polarized current and the direction of the exchange bias field exist one-to-one correspondence, so as to realize the magnetization deterministic flip without external field, and then reduce the power consumption of the device.

[0061] In some embodiments of the present application, the material of the anti-ferromagnetic layer is not only anti-ferromagnetic material, but also has spin-orbit coupling property.

[0062] The magnetic moments (i.e. magnetic directions) of atoms or ions in anti-ferromagnetic material are arranged in an ordered anti-parallel arrangement, i.e. the directions of adjacent magnetic moments are opposite. This arrangement causes these materials to exhibit zero net magnetic moment on a macroscopic scale, although each atom or ion has a magnetic moment on a microscopic scale.

[0063] Anti-ferromagnetic material loses its anti-ferromagnetic order above a certain temperature, and above the temperature (Néel temperature), the material exhibits paramagnetism.

[0064] The magnetization curve of the anti-ferromagnetic material shows a linear relationship at low temperature, and the magnetization intensity rises rapidly when approaching the Néel temperature.

[0065] Spin-orbit coupling (SOC) is a physical phenomenon describing the interaction between an electron's spin and orbital angular momentum. Specifically, it reflects the coupling between the electron's motion in an electric field (i.e., its orbital motion) and its spin state.

[0066] Electron spin is the intrinsic angular momentum of an electron, manifesting as a rotational-like motion. Spin is a quantum mechanical property, typically having only two possible states: up or down. Orbital angular momentum is the angular momentum of an electron orbiting the atomic nucleus. Orbital angular momentum is closely related to the electron's state of motion.

[0067] Spin-orbit coupling refers to the coupling between the orbital angular momentum and spin of an electron through electromagnetic interaction, a relativistic effect. Specifically, when an electron moves in an electric field, the electric field observed in its own frame of reference generates a magnetic field in that frame. This magnetic field acts on the electron itself, causing a change in the electron's spin state, thus forming a coupling effect.

[0068] In some embodiments of the present invention, the information storage medium is a vertical magnetic moment.

[0069] As can be seen from the above description, the magnetic storage device provided in the embodiments of the present invention includes: a ferromagnetic reference layer; a tunneling layer, one side of which is attached to the ferromagnetic reference layer; a ferromagnetic free layer, one side of which is attached to the other side of the tunneling layer; and an antiferromagnetic layer, attached to the other side of the ferromagnetic free layer; and the material is a non-mirror symmetrical antiferromagnetic material.

[0070] The magnetic storage device proposed in this invention replaces the heavy metal layer used in existing technologies to generate in-plane spin current with an antiferromagnetic layer exhibiting symmetry breaking, thereby achieving a high-performance magnetic storage device with fully electrically controlled operation. The out-of-plane spin polarization current generated by the antiferromagnetic layer can directly act on the vertical magnetic moment of the ferromagnetic free layer. Simultaneously, the exchange coupling formed between the antiferromagnetic layer and the ferromagnetic free layer generates an exchange bias field, improving the thermal stability of the vertical magnetic moment. Furthermore, the applied charge current can directly control the exchange bias field. There is a one-to-one correspondence between the direction of the applied charge current and the vertical spin polarization current and the direction of the exchange bias field, thus enabling deterministic magnetization reversal without an external field, thereby reducing the device's power consumption.

[0071] Next, see Figure 4 The present invention also provides a method for storing information using the above-described magnetic storage device, the method comprising:

[0072] Step 100: Generate an exchange bias field through the exchange coupling between the antiferromagnetic layer and the ferromagnetic free layer;

[0073] Step 200: Enhance the thermal stability of the vertical magnetic moment through the exchange bias field; wherein, the vertical magnetic moment is the carrier of information storage;

[0074] Step 300: Apply an external charge current to the antiferromagnetic layer to generate an out-of-plane spin polarization current;

[0075] Step 400: The vertical magnetic moment is flipped by the out-of-plane spin polarization current to store information.

[0076] As described above, embodiments of the present invention also provide a method for storing information using the aforementioned magnetic storage device. This method includes: generating an exchange bias field through exchange coupling between an antiferromagnetic layer and a ferromagnetic free layer; enhancing the thermal stability of the vertical magnetic moment through the exchange bias field; wherein the vertical magnetic moment serves as the carrier for information storage; applying an external charge current to the antiferromagnetic layer to generate an out-of-plane spin polarization current; and flipping the vertical magnetic moment through the out-of-plane spin polarization current to store the information. The present invention has the following beneficial effects:

[0077] First, improve thermal stability: By introducing an exchange bias field, the thermal stability of the vertical magnetic moment is enhanced, enabling the device to achieve stable storage at the sub-ten nanometer scale.

[0078] Next, the structure of the magnetic storage device is simplified and power consumption is reduced: the spin orbit moment generated by the out-of-plane spin current of the present invention realizes magnetization reversal without the assistance of an in-plane magnetic field, which simplifies the system design and significantly reduces power consumption during the writing process.

[0079] Finally, the write speed is improved: the application of out-of-plane spin orbital moment greatly improves the speed of magnetization reversal, making the write operation more efficient and suitable for high-speed storage application scenarios.

[0080] For steps 100 and 200, the exchange coupling between the antiferromagnetic layer and the ferromagnetic free layer will... Figure 1 An additional effective magnetic field (exchange bias field) is generated in the system shown, which increases the energy barrier between the two magnetic moment directions, thereby enhancing the thermal stability of the perpendicular magnetic moment (when the magnetic moment is perpendicular to the thin film plane) and achieving stable storage in the sub-ten nanometer range.

[0081] For steps 300 and 400, an external charge current is applied to generate an out-of-plane spin polarization current through the antiferromagnetic layer. This out-of-plane spin polarization current generates a vertical spin orbit moment in the ferromagnetic free layer. This spin orbit moment acts on the vertical magnetic moment in the ferromagnetic free layer, causing it to flip, thereby realizing the information writing operation.

[0082] Out-of-plane spin polarization current refers to the current carrying a spin polarization direction perpendicular to the surface of the thin film or material. Spin orbital moment refers to the torque generated by the coupling between spin and orbital degrees of freedom.

[0083] See Figure 5 In some embodiments of the present invention, step 400, which involves reversing the vertical magnetic moment through the out-of-plane spin polarization current, includes:

[0084] Step 401: Generate a spin orbital moment in the ferromagnetic free layer using the out-of-plane spin polarization current;

[0085] Step 402: Flip the vertical magnetic moment by means of the spin orbital moment.

[0086] In steps 401 and 402, the out-of-plane spin-polarized current generates a vertical spin orbital moment in the free layer. This spin orbital moment acts on the vertical magnetic moment in the ferromagnetic free layer, causing it to flip.

[0087] In some embodiments of the present invention, an information storage method further includes:

[0088] By using exchange bias fields in different directions, the ferromagnetic free layer has different energies in the +z direction and -z direction, thereby generating different magnetic ground states.

[0089] In some embodiments of the present invention, an information storage method further includes:

[0090] The vertical magnetic moment is flipped by the different magnetic ground states and the spin orbital moment.

[0091] Thanks to the assistance of the exchange bias field, the vertical magnetic moment can maintain stability at higher temperatures without requiring additional in-plane magnetic field assistance.

[0092] In some embodiments of the present invention, an information storage method further includes:

[0093] The vertical magnetic moment is deterministically flipped by controlling the direction of the applied charge current.

[0094] The introduction of the exchange bias field will make the energies of the +z and -z magnetization directions different, so that different directions of exchange bias field correspond to different magnetization ground states. Under the action of the out-of-plane spin orbital moment, the magnetization direction can be reversed.

[0095] In some embodiments of the present invention, the direction of the applied charge current, the polarization direction of the out-of-plane spin polarization current, and the direction of the exchange bias field are in a one-to-one correspondence.

[0096] Understandably, it is precisely because of this correspondence that deterministic magnetization reversal can be achieved without an external field, thereby reducing the power consumption of magnetic storage devices.

[0097] In some embodiments of the present invention, an information storage method further includes:

[0098] The vertical magnetic moment is deterministically flipped by controlling the direction of the applied charge current.

[0099] See Figure 6 In some embodiments of the present invention, the above-described method of deterministically reversing the vertical magnetic moment by controlling the direction of the applied charge current includes:

[0100] Step 801: Change the polarization direction of the out-of-plane spin polarization current by controlling the direction of the applied charge current;

[0101] Step 802: Change the exchange bias field by controlling the polarization direction of the out-of-plane spin polarization current;

[0102] Step 803: Deterministically flip the vertical magnetic moment by controlling the exchange bias field.

[0103] In steps 801 to 803, the introduction of the exchange bias field creates an energy difference between the two magnetization directions. For each defined field direction, there is a corresponding magnetization ground state. Therefore, the direction of the exchange bias field can be changed by adjusting the direction of the applied charge current. That is, the perpendicular magnetic moment direction is directly linked to the polarization direction of the out-of-plane spin-polarized current through the exchange bias field, and a deterministic reversal of the magnetic moment can be achieved by changing the current direction.

[0104] To further illustrate the solution, the present invention also provides a specific embodiment of the magnetic storage device, including the following:

[0105] The present invention aims to solve the key problems faced by existing spin-orbit moment magnetic storage devices, especially the problem of insufficient thermal stability and the need for in-plane magnetic field-assisted magnetization reversal when the vertical magnetic moment-based SOT devices are scaled down to sub-ten nanometer size.

[0106] First, this invention proposes a novel magnetic storage device based on an exchange bias field and out-of-plane spin orbital moment current. Second, this invention aims to improve the thermal stability and write efficiency of the storage device, simplify the magnetization reversal process, and reduce system complexity and power consumption, providing technical support for the development of next-generation high-density, low-power magnetic storage devices.

[0107] First, the storage cell structure during the aforementioned magnetic storage is provided. The storage cell uses a perpendicular magnetic moment as the carrier for information storage. Next, an exchange bias field is introduced to enhance the stability of the perpendicular magnetic moment through the exchange coupling between the antiferromagnetic layer and the ferromagnetic free layer, thereby improving the thermal stability of the storage cell and ensuring its stable operation at room temperature and higher temperatures.

[0108] Based on the aforementioned storage cell structure, this invention also proposes a novel writing mechanism. Specifically, it utilizes the spin orbital moment generated by out-of-plane spin current to induce a reversal of the magnetic moment in the ferromagnetic free layer.

[0109] See Figure 1 It is a magnetic tunnel junction based on out-of-plane spin current and exchange bias field. Without changing the materials used in the ferromagnetic reference layer, tunneling layer, and ferromagnetic free layer, the heavy metal material is replaced with a low-symmetry, strong spin-orbit coupling (SOC) antiferromagnetic material. Because of the symmetry breaking, the spin polarization current generated by the spin Hall effect also has an out-of-plane component, which can directly act on the vertical magnetic moment of the free layer.

[0110] Next, see Figure 7 , Figure 8 as well as Figure 9 For a system that does not have a commutative bias field, and The two magnetic moment ground states have the same energy magnitude, and there is no definite reversal direction during the flipping process. Furthermore, there is an energy barrier between the two magnetic moment ground states. That is, the energy barrier of perpendicular magnetic anisotropy of the material ( The value decreases rapidly with size reduction, making stable storage impossible. This is because the exchange coupling between the antiferromagnetic layer and the ferromagnetic free layer generates an additional effective magnetic field in the system. ), introducing an additional energy barrier ( ), raising the energy barrier between the two magnetic moment ground state directions ( This enhances the thermal stability of the vertical magnetic moment, enabling stable storage at sub-ten nanometer scale.

[0111] Furthermore, the introduction of the exchange bias field creates an energy difference between the two magnetization directions. For each defined field direction, there is a corresponding magnetization ground state. During magnetic moment reversal, the in-plane magnetic moment flips towards the direction with the lower magnetic moment ground state energy, thus achieving assisted deterministic magnetization reversal. Therefore, the polarization directions of the exchange bias field and the out-of-plane spin polarization current can be changed by adjusting the direction of the applied charge current. The exchange bias field directly links the perpendicular magnetic moment direction with the polarization direction of the out-of-plane spin polarization current; that is, deterministic magnetic moment reversal can be achieved by changing the current direction.

[0112] Unlike existing technologies that require an in-plane magnetic field to assist magnetization reversal, this invention achieves deterministic reversal of vertical magnetization by directly applying an out-of-plane spin current and an exchange bias field between the free layer and the antiferromagnetic material to the vertical magnetic moment. This innovation not only simplifies the device structure but also significantly reduces power consumption during write operations.

[0113] As can be seen from the above description, the specific embodiments of the present invention also provide a method for storing information using the above-mentioned magnetic storage device. The method includes: generating an exchange bias field through the exchange coupling between the antiferromagnetic layer and the ferromagnetic free layer; enhancing the thermal stability of the vertical magnetic moment through the exchange bias field; wherein the vertical magnetic moment is the carrier of information storage; applying an external charge current to the antiferromagnetic layer to generate an out-of-plane spin polarization current; and controlling the polarization direction of the out-of-plane spin polarization current to flip the vertical magnetic moment in order to store information.

[0114] This invention aims to address key issues faced by existing spin-orbit moment magnetic storage devices, particularly the insufficient thermal stability and the need for in-plane magnetic field-assisted magnetization reversal in vertical magnetic moment-based SOT devices when scaled down to sub-10 nanometer dimensions. This invention can improve the thermal stability and write efficiency of storage devices, simplify the magnetization reversal process, and reduce system complexity and power consumption, providing technical support for the development of next-generation high-density, low-power magnetic storage devices.

[0115] In the description of this specification, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of the invention, unless otherwise stated, "a plurality of" means two or more.

[0116] The terms "an embodiment," "a specific embodiment," "some embodiments," "for example," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. The order of steps involved in the various embodiments is used to illustrate the implementation of the present invention, and the order of steps is not limited and may be adjusted as needed.

[0117] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0118] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, system embodiments are basically similar to method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. In the description of this specification, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments in this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0119] The above description is merely an embodiment of the present specification and is not intended to limit the embodiments of the present specification. For those skilled in the art, various modifications and variations can be made to the embodiments of the present specification. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the embodiments of the present specification should be included within the scope of the claims of the embodiments of the present specification.

Claims

1. A method for storing information using a magnetic storage device, characterized in that, include: An exchange bias field is generated through the exchange coupling between the antiferromagnetic layer and the ferromagnetic free layer; The antiferromagnetic layer is attached to the other side of the ferromagnetic free layer; and the material is an antiferromagnetic material with mirror-symmetry defects. The thermal stability of the vertical magnetic moment is enhanced by the exchange bias field; wherein, the vertical magnetic moment is a carrier for information storage. An external charge current is applied to the antiferromagnetic layer to generate an out-of-plane spin polarization current; The vertical magnetic moment is flipped by the out-of-plane spin polarization current to store information; The vertical magnetic moment is flipped by the out-of-plane spin polarization current, including: Spin orbital moments are generated in the ferromagnetic free layer by the out-of-plane spin polarization current; The vertical magnetic moment is flipped by the spin orbital moment; The method for storing information further includes: By using exchange bias fields in different directions, the ferromagnetic free layer has different energies in the +z direction and -z direction, thereby generating different magnetic ground states; The direction of the applied charge current, the polarization direction of the out-of-plane spin polarization current, and the direction of the exchange bias field are in one-to-one correspondence. The method for storing information further includes: The vertical magnetic moment is deterministically flipped by controlling the direction of the applied charge current; The method of deterministically reversing the vertical magnetic moment by controlling the direction of the applied charge current includes: The polarization direction of the out-of-plane spin polarization current can be changed by controlling the direction of the applied charge current; The exchange bias field is changed by controlling the polarization direction of the out-of-plane spin polarization current; The vertical magnetic moment is deterministically flipped by controlling the exchange bias field. Specifically, the introduction of the exchange bias field causes an energy difference between the two magnetization directions. For each determined field direction, there will be a corresponding magnetization ground state. Therefore, the direction of the exchange bias field can be changed by adjusting the direction of the applied charge current. That is, the direction of the vertical magnetic moment is directly linked to the polarization direction of the out-of-plane spin polarization current by the exchange bias field. The deterministic flipping of the magnetic moment is achieved by changing the direction of the current.

2. The information storage method according to claim 1, characterized in that, Also includes: The vertical magnetic moment is flipped by the different magnetic ground states and the spin orbital moment.

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