Method and device for regulating and controlling spin orbit moment efficiency based on antiferromagnetic heterojunction

Abstract

The invention provides a method and device for regulating and controlling spin orbit moment efficiency based on an antiferromagnetic heterojunction, and belongs to the field of spin electronic devices. The method comprises the following steps: after a film stack of an antiferromagnetic heterojunction grows and is processed into a spin-orbit moment device, applying an added field in a first magnetic field direction to the antiferromagnetic heterojunction at room temperature for cooling, and cooling to an ultralow temperature environment, and the Nell magnetic sequence direction of the antiferromagnetic layer in the antiferromagnetic heterojunction is changed relative to the spin polarization direction of the spin current generated by the heavy metal layer, so that the transport process of the spin current generated by the heavy metal layer in antiferromagnetic is changed, and the spin orbit moment efficiency and the critical flip current density of the antiferromagnetic heterojunction are regulated and controlled. The first magnetic field direction is parallel to the Y-axis direction of the rectangular coordinate system where the heavy metal layer is located. According to the invention, after the film stack is processed into a device, the spin transport process in the antiferromagnetic heterostructure can be regulated and controlled in a field-adding cooling manner, so that the spin orbit moment efficiency can be regulated and controlled.

Description

Technical Field

[0001] The present invention relates to the field of spin electronic devices, and in particular to a method for regulating spin-orbit torque efficiency based on an antiferromagnetic heterojunction and a spin-orbit torque device. Background Art

[0002] Magnetic random access memory (MRAM) based on the tunneling magnetoresistance effect (TMR) uses the properties of electron spin and has the characteristics of high speed, high density and low power consumption. It is usually used in non-volatile microelectronic devices. Among them, the technology of using spin-orbit torque (SOT) to flip the magnetic moment has the advantages of pure current drive, read-write path separation, and high integration. The spin-orbit moment efficiency is an important indicator to measure the power consumption of spin electronics devices. The greater the spin-orbit moment efficiency, the less power consumption the device requires. The main factors affecting the spin-orbit moment efficiency are the spin Hall angle of the SOT generation layer and the transmission process of the spin current.

[0003] The existing technologies for regulating the efficiency of spin-orbit moment are mainly through heavy metal alloying, oxygen (nitrogen) gas treatment, orbital Hall effect synergy or body Rashaba effect synergy. The above methods all enhance the SOT efficiency by changing the SOT generation layer, but ignore the transmission process of the spin current from the SOT generation layer to the ferromagnetic layer. Moreover, the existing technologies all complete the regulation of SOT efficiency during the film stack thin film preparation process, and the spin-orbit moment efficiency cannot be regulated on a large scale after the film stack preparation is completed. Summary of the invention

[0004] In order to solve the above technical defects, the present invention provides a method for regulating the efficiency of spin-orbit torque based on antiferromagnetic heterojunction and a spin-orbit torque device.

[0005] On one hand, the present invention provides a method for regulating the efficiency of spin-orbit moment based on an antiferromagnetic heterojunction, wherein the antiferromagnetic heterojunction comprises a heavy metal layer, an antiferromagnetic layer and a ferromagnetic layer stacked in sequence, and the method comprises: after the film stack of the antiferromagnetic heterojunction is grown and processed into a spin-orbit moment device, applying field cooling in a first magnetic field direction to the antiferromagnetic heterojunction at room temperature, and cooling to an ultra-low temperature environment, so that the Née magnetic order direction of the antiferromagnetic layer in the antiferromagnetic heterojunction changes relative to the spin polarization direction of the spin current generated by the heavy metal layer, so as to change the transport process of the spin current generated by the heavy metal layer in the antiferromagnetic layer, and realize the regulation of the spin-orbit moment efficiency and the critical flip current density of the antiferromagnetic heterojunction; the first magnetic field direction is parallel to the Y-axis direction of the rectangular coordinate system where the heavy metal layer is located.

[0006] In the embodiment of the present invention, the temperature of the ultra-low temperature environment is determined according to the thickness of the antiferromagnetic layer; the thickness of the antiferromagnetic layer is 2 nm, and the temperature of the ultra-low temperature environment is 10 Kelvin to 180 Kelvin.

[0007] In an embodiment of the present invention, the method further comprises: applying field cooling in a second magnetic field direction to the antiferromagnetic heterojunction;

[0008] The angle between the second magnetic field direction and the first magnetic field in-plane direction is 0° to 90°.

[0009] In an embodiment of the present invention, the method further includes: adjusting the magnetic field strength of the first magnetic field direction or the second magnetic field direction based on an angle between the second magnetic field direction and the first magnetic field in-plane direction.

[0010] Another aspect of the present invention provides a spin-orbit torque device, comprising: a heavy metal layer (HM), an antiferromagnetic layer (AFM) and a magnetic tunnel junction, wherein the magnetic tunnel junction comprises a first ferromagnetic layer, a tunneling layer and a second ferromagnetic layer stacked in sequence, the antiferromagnetic layer is located on the surface of the heavy metal layer, and the first ferromagnetic layer is located on the surface of the antiferromagnetic layer;

[0011] The heavy metal layer, the antiferromagnetic layer and the first ferromagnetic layer form an antiferromagnetic heterojunction;

[0012] After the film stack of the antiferromagnetic heterojunction is grown and processed into a spin-orbit torque device, field cooling in the direction of a first magnetic field is applied at room temperature and cooled to an ultra-low temperature environment, so that the Née magnetic order direction of the antiferromagnetic layer in the antiferromagnetic heterojunction changes relative to the spin polarization direction of the spin current generated by the heavy metal layer, so as to change the transport process of the spin current generated by the heavy metal layer in the antiferromagnetic layer, thereby realizing the regulation of the spin-orbit torque efficiency and critical reversal current density of the antiferromagnetic heterojunction; the first magnetic field direction is parallel to the Y-axis direction of the rectangular coordinate system where the heavy metal layer is located.

[0013] In the embodiment of the present invention, the temperature of the ultra-low temperature environment is determined according to the thickness of the antiferromagnetic layer; the thickness of the antiferromagnetic layer is 2 nm, and the temperature of the ultra-low temperature environment is 10 Kelvin to 180 Kelvin.

[0014] In an embodiment of the present invention, the antiferromagnetic heterojunction is further cooled by applying a second magnetic field direction in an ultra-low temperature environment;

[0015] The angle between the second magnetic field direction and the first magnetic field in-plane direction is 0° to 90°.

[0016] In an embodiment of the present invention, the material of the heavy metal layer is a combination of one or more of Pt, W, and Ta.

[0017] In an embodiment of the present invention, the material of the antiferromagnetic layer is a combination of one or more of IrMn, PtMn, FeMn and PdMn.

[0018] In the embodiment of the present invention, the materials of the first ferromagnetic layer, the tunneling layer and the second ferromagnetic layer are CoFeB, MgO and CoFeB respectively;

[0019] Alternatively, the materials of the first ferromagnetic layer, the tunneling layer and the second ferromagnetic layer are CoFeSiB, MgO and CoFeSiB respectively.

[0020] The present invention adds an antiferromagnetic layer between the heavy metal layer and the ferromagnetic layer to form an antiferromagnetic heterojunction. After the film stack of the antiferromagnetic heterojunction is grown, or after the film stack is processed into a device, the antiferromagnetic heterojunction is subjected to field cooling in the first magnetic field direction, so that the Née magnetic order direction of the antiferromagnetic layer of the antiferromagnetic heterojunction changes relative to the spin polarization direction of the spin current generated by the heavy metal layer, thereby changing the critical reversal current density of the heavy metal layer, thereby changing the transport process of the spin current generated by the heavy metal layer in the antiferromagnetic layer, and realizing the regulation of the spin-orbit moment efficiency of the antiferromagnetic heterojunction; at the same time, the magnetization reversal information is read, and a low-power, high-density non-volatile spin electronic device is realized. The spin-orbit moment efficiency regulation method provided by the present invention can regulate the spin-orbit moment efficiency of the antiferromagnetic heterojunction after the film stack is prepared and processed into a spin-orbit moment device, and is more flexible.

[0021] Other features and advantages of the technical solution of the present invention will be described in detail in the specific implementation section below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 is a schematic structural diagram of an antiferromagnetic heterojunction provided in an embodiment of the present invention;

[0024] Figure 2 It is a schematic diagram of the spin transport process in an antiferromagnetic heterojunction (the Née magnetic order of the antiferromagnetic layer is parallel to the spin polarization direction of the heavy metal layer);

[0025] Figure 3 It is a schematic diagram of the spin transport process in an antiferromagnetic heterojunction (the Née magnetic order of the antiferromagnetic layer is perpendicular to the spin polarization direction of the heavy metal layer);

[0026] Figure 4 is a graph of the exchange bias field between the antiferromagnetic layer and the ferromagnetic layer in an antiferromagnetic heterojunction and temperature;

[0027] Figure 5 The ST-FMR device is subjected to field cooling in different directions (H FC )

[0028] Figure 6 This is the relationship between the spin-orbit moment efficiency and temperature of the ST-FMR device under field cooling in different directions;

[0029] Figure 7 It is a schematic diagram of the flip test of the Hall target device;

[0030] Figure 8 This is a comparison of the magnetization reversal current density of the Hall target device under field cooling in different directions;

[0031] Fig. 9 It is a schematic diagram of the structure of a spin-orbit torque device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "surface", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. The terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0034] As introduced in the background technology, the existing technologies for regulating the efficiency of spin-orbit moment are mainly through heavy metal alloying, oxygen (nitrogen) gas treatment, orbital Hall effect synergy or body Rashaba effect synergy and other means. The above methods are to enhance the SOT efficiency by changing the SOT generation layer, but ignore the transmission process of the spin current from the SOT generation layer to the ferromagnetic layer. Moreover, in the prior art, the SOT efficiency is regulated during the film stack thin film preparation process, and the spin-orbit moment efficiency cannot be regulated on a large scale after the film stack preparation is completed.

[0035] For example, the patent application with application number "202211273801.6" and titled "A method for regulating the efficiency of spin-orbit moment based on orbital engineering" uses transition metal oxides as the film layer structure. By changing the substrate material for growth and the stress-strain state in the heterojunction, the transition metal electron orbital occupancy state and the spin-orbit coupling strength are regulated, and the spin-orbit moment is intrinsically regulated from the perspective of orbital physics, and the efficiency of the spin-orbit moment is improved. The gate voltage is provided through the ionic liquid electric field to achieve the regulation of the spin-orbit coupling strength of the heavy metal layer, thereby achieving the effect of improving the efficiency of the spin-orbit moment. The defects of this solution are: the film layers used are all transition metal oxides, which do not conform to the metal film stacks used in the industry; the ionic liquids used are not suitable for the wafer taping process in the industry, especially the high-temperature annealing process (ionic liquid evaporation) in the industry; they cannot work at ultra-low temperatures (ionic liquid freezing), especially for low-temperature storage and other fields.

[0036] The patent application number is "202211369688.1", and the name is "A method for regulating the spin-orbit torque efficiency through an interface modification layer". The technical solution improves the spin-orbit torque efficiency by inserting an interface modification layer between the SOT generation layer and the free layer of the magnetic tunnel junction. The interface modification layer used is MgO or tungsten nitride (WN), which is used to improve the spin transparency of the interface and thus improve the spin current transport. And by changing the thickness of the modification layer, the spin-orbit moment efficiency is regulated. The defect of this scheme is that the regulation method is single, and the spin-orbit moment can only be regulated by changing the thickness of the modification layer. After the growth of the membrane stack structure is completed, a large range of spin-orbit moment efficiency regulation cannot be continued.

[0037] In order to better regulate the efficiency of spin-orbit moment, the present invention provides a method for regulating the efficiency of spin-orbit moment based on antiferromagnetic heterojunction, which regulates the efficiency of spin-orbit moment based on the magnetic order of antiferromagnetism, thereby obtaining a high-efficiency spin electronics device. The present invention adopts a metal film stack commonly used in the industry, adds an antiferromagnetic layer between a heavy metal layer (SOT generation layer) and a ferromagnetic layer to form an antiferromagnetic heterojunction, and after the film stack of the antiferromagnetic heterojunction is grown and processed into a spin-orbit moment device, the antiferromagnetic heterojunction is subjected to field cooling in the direction of a first magnetic field at room temperature, and cooled to an ultra-low temperature environment, so that the Née magnetic order direction of the antiferromagnetic layer in the antiferromagnetic heterojunction changes relative to the spin polarization direction of the spin current generated by the heavy metal layer, so as to change the transport process of the spin current generated by the heavy metal layer in the antiferromagnetism, and realize the regulation of the spin-orbit moment efficiency and critical reversal current density of the antiferromagnetic heterojunction; at the same time, the reading of magnetization reversal information is realized, and a low-power, high-density non-volatile spin electronics device is realized. The spin-orbit torque efficiency control method provided by the present invention can control the spin-orbit torque efficiency of the antiferromagnetic heterojunction after the film stack is prepared and processed into a spin-orbit torque device, and is more flexible.

[0038] In addition, in addition to applying added field cooling in the first magnetic field direction to the antiferromagnetic heterojunction, added field cooling in the second magnetic field direction can also be applied to the antiferromagnetic heterojunction, wherein the angle between the second magnetic field direction and the in-plane direction of the first magnetic field is 0° to 90°, thereby achieving a wide range of control over the spin-orbit moment efficiency of the antiferromagnetic heterojunction.

[0039] Figure 1 Schematic diagram of the structure of the antiferromagnetic heterojunction provided by the embodiment of the present invention. Figure 1 As shown, the antiferromagnetic heterojunction of the embodiment of the present invention is composed of a heavy metal layer (HM), an antiferromagnetic layer (AFM) and a ferromagnetic layer (FM) stacked in sequence. The material of the heavy metal layer can be selected from one or more heavy metal materials with strong spin-orbit coupling such as Pt, W, Ta, etc.; the material of the antiferromagnetic layer can be selected from one of IrMn, PtMn, FeMn, PdMn, or a combination of multiple materials of IrMn, PtMn, FeMn, PdMn in different composition ratios; the material of the ferromagnetic layer can be selected from CoFeB or CoFeSiB.

[0040] Spin transport process in antiferromagnetic heterojunction (HM / AFM / FM): After the film stack structure of the antiferromagnetic heterojunction is grown, the corresponding spin electronic device is formed through standard micro-nano processing technology. When the write current is added to the device, the heavy metal layer generates a spin current through the spin Hall effect and flows to the interface between the heavy metal layer and the antiferromagnetic layer, and the magnetic oscillators of the antiferromagnetic layer are excited through the interface exchange. Finally, the magnetic oscillators and spin electrons pass through the antiferromagnetic layer together and act on the ferromagnetic layer to achieve the magnetization reversal of the ferromagnetic layer. In the above process, the transport of magnetic oscillators in the antiferromagnetic layer is strongly correlated with the Néel magnetic order of the antiferromagnetic and the spin polarization direction of the spin current generated by the heavy metal.

[0041] Figure 2 and Figure 3 Represents the spin transport process in the antiferromagnetic heterojunction (HM / AFM / FM). M represents magnon transport, and Js represents electron spin transport. Figure 2 It means that the Néel magnetic order is parallel to the spin polarization direction. Figure 3 It means that the Néel magnetic order is perpendicular to the spin polarization direction. Figure 2 As shown in , when the Née's magnetic order is parallel to the spin polarization direction, the number of excited magnons is the largest and the spin transport is the strongest; Figure 3 As shown in the figure, when the Née's magnetic order is perpendicular to the spin polarization direction, the number of excited magnons is the least and the spin transport is the weakest. Therefore, by changing the relative direction of the Née's magnetic order, the spin-orbit moment efficiency of the corresponding device can be adjusted.

[0042] Due to the exchange bias effect at the interface between the antiferromagnetic layer and the ferromagnetic layer, the direction of the Née magnetic order of the antiferromagnetic layer can be made parallel to the direction of the external magnetic field that forms the exchange bias. The present invention regulates the Née magnetic order of the antiferromagnetic layer by changing the direction of the external magnetic field during field cooling or annealing cooling, thereby achieving regulation of the transport of magnons and further regulating the spin-orbit moment efficiency of the corresponding device.

[0043] In this embodiment, the film stack thickness of the antiferromagnetic layer is 2 nm, and it does not exhibit antiferromagnetism at room temperature. Figure 4 This is a graph showing the relationship between the exchange bias field and temperature between the antiferromagnetic layer and the ferromagnetic layer. In the graph, the unit of temperature is K (Kelvin), the starting point of the Kelvin temperature scale is absolute zero (-273.15°C), T = t + 273.15°C, T represents the Kelvin temperature scale, and t represents the Celsius temperature scale. Figure 4 As shown, the antiferromagnetic layer has no exchange bias field at room temperature and its blocking temperature is 150K, indicating that the antiferromagnetic layer has long-range antiferromagnetic order at low temperature.

[0044] for Figure 1The antiferromagnetic heterojunction shown in the figure, after the film stack of the antiferromagnetic heterojunction is grown and the device processing is completed, the antiferromagnetic heterojunction is subjected to field cooling in the first magnetic field direction at room temperature, that is, cooling is performed under an external magnetic field until it is cooled to an ultra-low temperature. The antiferromagnetic heterojunction is cooled to an ultra-low temperature environment, so that the Nel magnetic order direction of the antiferromagnetic layer in the antiferromagnetic heterojunction changes relative to the spin polarization direction of the spin current generated by the heavy metal layer, thereby changing the transport process of the spin current generated by the heavy metal layer in the antiferromagnetic layer, and realizing the regulation of the spin-orbit moment efficiency and critical flip current density of the antiferromagnetic heterojunction. The first magnetic field direction is parallel to the Y-axis direction of the rectangular coordinate system where the heavy metal layer is located. Among them, the temperature of the ultra-low temperature environment of the field cooling can be determined according to the thickness of the antiferromagnetic layer. Usually, the thickness of the antiferromagnetic layer is 1nm to 4nm, and the temperature of the field cooling environment is 10K to 300K. For example, the thickness of the antiferromagnetic layer is preferably 2nm, and the temperature of the ultra-low temperature environment of the field cooling is preferably 50K to 150K.

[0045] In another embodiment, for Figure 1 For the antiferromagnetic heterojunction shown, after the film stack is grown, the antiferromagnetic heterojunction can also be subjected to field cooling in the second magnetic field direction at room temperature, or the magnetic field strength in the first magnetic field direction or the second magnetic field direction can be adjusted based on the angle between the second magnetic field direction and the first magnetic field in-plane direction. Specifically, the angle between the second magnetic field direction and the first magnetic field in-plane direction can be selected to be 0° to 90°. For example, when the angle between the first magnetic field direction and the second magnetic field direction is 30°, the magnetic field strength in the second magnetic field direction is 1 / 2 of the magnetic field strength in the first magnetic field direction. By adding field cooling in the first magnetic field direction and the second magnetic field direction with different magnetic field strengths, the spin-orbit moment efficiency of the antiferromagnetic heterojunction can be adjusted over a large range.

[0046] In a specific example, a Pt / IrMn / FM antiferromagnetic heterojunction is used and processed into a spin torque-ferromagnetic resonance (ST-FMR) device and a Hall target device through standard micro-nano processing technology. The spin torque-ferromagnetic resonance (ST-FMR) device is used for the characterization test of the spin-orbit torque efficiency, and the Hall target device is used for the test of magnetization reversal.

[0047] The ST-FMR device was tested for field cooling in two directions at room temperature. Figure 5 As shown, the first external magnetic field H FC Direction parallel to the Y axis (H FC ∥Y), the second external magnetic field H FC Direction parallel to the X axis (H FC ∥X). The coordinate axes define the antiferromagnetic heterojunction composed of a relatively heavy metal layer or a relatively heavy metal layer, an antiferromagnetic layer, and a ferromagnetic layer. FC∥Y corresponds to the Née magnetic order direction of the antiferromagnetic layer being parallel to the spin polarization direction of the heavy metal layer, H FC ∥X corresponds to the Néel magnetic order direction of the antiferromagnetic layer being perpendicular to the spin polarization direction of the heavy metal layer. The test results are as follows Figure 6 As shown, in the temperature range of 10K to 180K, H FC ∥The spin-orbit moment efficiency of Y is higher than that of H FC The spin-orbit efficiency of ∥X is the largest when it is around 100K. In the range of 100K to 180K, the spin-orbit efficiency gradually decreases because the antiferromagnetic order gradually weakens with the increase in temperature, resulting in a decrease in the relaxation length of the magnon, which leads to a decrease in the spin-orbit efficiency. It can be seen that in the low temperature region, the temperature is correlated with the Née magnetic order of the antiferromagnetic layer. The spin-orbit efficiency can be regulated in different temperature regions by changing the material type or thickness of the antiferromagnetic layer.

[0048] The magnetization reversal test of the Hall target device was carried out in an ultra-low temperature environment. Similarly, field cooling tests were carried out in two directions. The first one was the external magnetic field H FC Direction parallel to the Y axis (H FC ∥Y), the second external magnetic field H FC Direction parallel to the X axis (H FC ∥X), the coordinate axis is defined as Figure 7 As shown. A pulse current Ipluse is applied to the long axis of the Hall target device, and the resistance is read at the short axis to record its magnetization reversal process. Figure 8 As shown, at 100K, H FC The critical reversal current density under the configuration of ∥Y is ±0.9×10 7 A / cm 2 , less than H FC Current density under ∥X configuration ±1.2×10 7 A / cm 2 The test results show that by regulating the relationship between the antiferromagnetic Néel magnetic order and the spin polarization direction, the magnetization reversal current density can be effectively regulated, thereby improving the spin-orbit moment efficiency. Because the magnetization reversal current density is low, it means that the power consumption required by the device is small. The spin current transmission process can be realized under low power consumption, which improves the spin-orbit moment efficiency.

[0049] Based on the above method for regulating the efficiency of spin-orbit torque, an embodiment of the present invention further provides a spin-orbit torque device. Fig. 9As shown, the spin-orbit torque device of this embodiment includes: a heavy metal layer (HM), an antiferromagnetic layer (AFM) and a magnetic tunnel junction, the magnetic tunnel junction includes a first ferromagnetic layer (FM), a tunneling layer (MgO) and a second ferromagnetic layer (FM) stacked in sequence, the antiferromagnetic layer (AFM) is located on the surface of the heavy metal layer (HM), and the first ferromagnetic layer (FM) is located on the surface of the antiferromagnetic layer (AFM). The heavy metal layer (HM), the antiferromagnetic layer (AFM) and the first ferromagnetic layer (FM) constitute an antiferromagnetic heterojunction.

[0050] The heavy metal layer (HM), the antiferromagnetic layer (AFM), the first ferromagnetic layer (FM), the tunneling layer (MgO) and the second ferromagnetic layer (FM) are formed by micro-nano processing technology. After the film stack of the heavy metal layer (HM), the antiferromagnetic layer (AFM) and the first ferromagnetic layer (FM) is grown and processed into a spin-orbit torque device, the first magnetic field direction is applied at room temperature for field cooling, and cooled to an ultra-low temperature environment, so that the Nel magnetic order direction of the antiferromagnetic layer (AFM) changes relative to the spin polarization direction of the spin current generated by the heavy metal layer (HM), so as to change the transport process of the spin current generated by the heavy metal layer (HM) in the antiferromagnetic layer, and realize the regulation of the spin-orbit torque efficiency and critical flip current density of the antiferromagnetic heterojunction. Among them, the first magnetic field direction is parallel to the Y-axis direction of the rectangular coordinate system where the heavy metal layer is located. The temperature of the ultra-low temperature environment of the field cooling can be determined according to the thickness of the antiferromagnetic layer. Typically, the thickness of the antiferromagnetic layer is 1 nm to 3 nm, and the temperature of the ultra-low temperature environment is 10 K to 300 K. For example, the thickness of the antiferromagnetic layer is preferably 2 nm, and the temperature of the ultra-low temperature environment is preferably 50 K to 150 K.

[0051] In other embodiments, after the film stack of the antiferromagnetic heterojunction is grown, the antiferromagnetic heterojunction is subjected to field cooling in the second magnetic field direction at room temperature, or the magnetic field strength in the first magnetic field direction or the second magnetic field direction is adjusted based on the angle between the second magnetic field direction and the first magnetic field in-plane direction. Specifically, the angle between the second magnetic field direction and the first magnetic field in-plane direction can be selected to be 0° to 90°. For example, when the angle between the first magnetic field direction and the second magnetic field direction is 30°, the magnetic field strength in the second magnetic field direction is 1 / 2 of the magnetic field strength in the first magnetic field direction. By adding field cooling in the first magnetic field direction and the second magnetic field direction with different magnetic field strengths, the spin-orbit moment efficiency of the antiferromagnetic heterojunction can be adjusted over a large range.

[0052] In a specific embodiment, the material of the heavy metal layer can be selected from one or more heavy metal materials with strong spin-orbit coupling such as Pt, W, Ta, etc.; the material of the antiferromagnetic layer can be selected from one of IrMn, PtMn, FeMn, PdMn, or a combination of multiple materials of IrMn, PtMn, FeMn, PdMn in different composition ratios; the material of the ferromagnetic layer can be selected from CoFeB or CoFeSiB. The materials of the first ferromagnetic layer, the tunneling layer and the second ferromagnetic layer of the magnetic tunnel junction are CoFeB, MgO, CoFeB in sequence; or, are CoFeSiB, MgO, CoFeSiB, etc. in sequence.

[0053] The method for regulating the spin-orbit moment efficiency and the spin-orbit moment device of the present invention can achieve the regulation of the spin transport process in the HM / AFM / FM antiferromagnetic heterostructure by annealing or cooling after the film stack is processed into a device, thereby achieving the regulation of the spin-orbit moment efficiency instead of changing the SOT generating layer, and the regulation is not achieved solely by changing the film stack structure.

[0054] The present invention can also achieve regulation of the spin-orbit moment efficiency in different temperature regions by changing the type and thickness of the antiferromagnetic layer (AFM), rather than just achieving regulation at room temperature.

[0055] In addition, the membrane stack structures used in the present invention are all materials commonly used in the industry, which are consistent with the requirements of the tape-out process, and do not require materials with special lattice structures to achieve the regulation of spin-orbit moment efficiency. The spin-orbit moment device of the present invention can be prepared in large areas and batches using industrialized micro-nano processing and manufacturing technology, and has the advantage of low cost.

[0056] The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, a variety of simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction, and as long as the combination does not violate the concept of the embodiments of the present invention, it should also be regarded as the content disclosed in the embodiments of the present invention.

Claims

1. A method for regulating spin-orbit moment efficiency based on an antiferromagnetic heterojunction, wherein the antiferromagnetic heterojunction comprises a heavy metal layer, an antiferromagnetic layer and a ferromagnetic layer stacked in sequence, characterized in that: The method comprises: After the film stack of the antiferromagnetic heterojunction is grown and processed into a spin-orbit torque device, the antiferromagnetic heterojunction is subjected to field cooling in a first magnetic field direction at room temperature, and cooled to an ultra-low temperature environment, so that the Née magnetic order direction of the antiferromagnetic layer in the antiferromagnetic heterojunction is changed relative to the spin polarization direction of the spin current generated by the heavy metal layer, so as to change the transport process of the spin current generated by the heavy metal layer in the antiferromagnetic layer, thereby realizing the regulation of the spin-orbit torque efficiency and critical reversal current density of the antiferromagnetic heterojunction; The first magnetic field direction is parallel to the Y-axis direction of the rectangular coordinate system where the heavy metal layer is located.

2. The method for regulating spin-orbit moment efficiency based on antiferromagnetic heterojunction according to claim 1, characterized in that: The temperature of the ultra-low temperature environment is determined according to the thickness of the antiferromagnetic layer; The thickness of the antiferromagnetic layer is 2 nm, and the temperature of the ultra-low temperature environment is 10 Kelvin to 180 Kelvin.

3. The method for regulating spin-orbit moment efficiency based on antiferromagnetic heterojunction according to claim 1, characterized in that: The method further comprises: Applying field cooling in a second magnetic field direction to the antiferromagnetic heterojunction; The angle between the second magnetic field direction and the first magnetic field in-plane direction is 0° to 90°.

4. The method for regulating spin-orbit moment efficiency based on antiferromagnetic heterojunction according to claim 3, characterized in that: The method further comprises: Based on the angle between the second magnetic field direction and the first magnetic field in-plane direction, the magnetic field strength of the first magnetic field direction or the second magnetic field direction is adjusted.

5. A spin-orbit torque device, characterized in that: include: A heavy metal layer, an antiferromagnetic layer and a magnetic tunnel junction, wherein the magnetic tunnel junction comprises a first ferromagnetic layer, a tunnel layer and a second ferromagnetic layer stacked in sequence, the antiferromagnetic layer is located on the surface of the heavy metal layer, and the first ferromagnetic layer is located on the surface of the antiferromagnetic layer; The heavy metal layer, the antiferromagnetic layer and the first ferromagnetic layer form an antiferromagnetic heterojunction; After the film stack of the antiferromagnetic heterojunction is grown and processed into a spin-orbit torque device, field cooling in the direction of a first magnetic field is applied at room temperature and cooled to an ultra-low temperature environment, so that the Née magnetic order direction of the antiferromagnetic layer in the antiferromagnetic heterojunction changes relative to the spin polarization direction of the spin current generated by the heavy metal layer, so as to change the transport process of the spin current generated by the heavy metal layer in the antiferromagnetic layer, thereby realizing the regulation of the spin-orbit torque efficiency and critical reversal current density of the antiferromagnetic heterojunction; the first magnetic field direction is parallel to the Y-axis direction of the rectangular coordinate system where the heavy metal layer is located.

6. The spin-orbit torque device according to claim 5, characterized in that: The temperature of the ultra-low temperature environment is determined according to the thickness of the antiferromagnetic layer; The thickness of the antiferromagnetic layer is 2 nm, and the temperature of the ultra-low temperature environment is 10 Kelvin to 180 Kelvin.

7. The spin-orbit torque device according to claim 5, characterized in that: The antiferromagnetic heterojunction is also cooled by applying a second magnetic field direction in an ultra-low temperature environment; The angle between the second magnetic field direction and the first magnetic field in-plane direction is 0° to 90°.

8. The spin-orbit torque device according to claim 5, characterized in that: The material of the heavy metal layer is one or more combinations of Pt, W and Ta.

9. The spin-orbit torque device according to claim 5, characterized in that: The material of the antiferromagnetic layer is a combination of one or more of IrMn, PtMn, FeMn and PdMn.

10. The spin-orbit torque device according to claim 5, characterized in that: The materials of the first ferromagnetic layer, the tunneling layer and the second ferromagnetic layer are CoFeB, MgO and CoFeB respectively; Alternatively, the materials of the first ferromagnetic layer, the tunneling layer and the second ferromagnetic layer are CoFeSiB, MgO and CoFeSiB respectively.

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