Ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance regulation and control method

Abstract

The invention provides a ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance regulation and control method, which comprises the following steps of: introducing an antiferromagnetic insulating layer between a ferromagnetic metal layer and a substrate under the conditions of not changing a heavy metal material and not damaging a ferromagnetic / heavy metal interface, and regulating and controlling the direction of a neel vector of the antiferromagnetic insulating layer, so that the ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance is obtained. Reflection and absorption of ferromagnetic / heavy metal heterojunction spin current are regulated and controlled so as to change the size and sign of spin Hall magnetoresistance.

Description

Technical Field

[0001] The invention relates to the technical field of novel magnetoresistance, and in particular to a method for regulating ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance. Background Art

[0002] SMR is a new type of magnetoresistance effect found in ferromagnetic / heavy metal heterojunction structures. SMR can be used to effectively extract the spin Hall angle of the heavy metal layer and detect magnetic anisotropy, interface magnetic structure and other magnetic performance parameters of magnetic materials. In addition, ferromagnetic / heavy metal heterojunctions are the core structural units for building third-generation magnetic random access memory, and have very important research significance and potential application value in spin electronics.

[0003] The so-called SMR is a magnetoresistance effect related to the magnetic moment direction of the ferromagnetic layer, which is based on the Spin Hall effect (SHE) and Inverse Spin Hall effect (ISHE) of heavy metals. The principle is as follows: when current flows through heavy metal materials, a spin current perpendicular to the current direction will be generated due to the Spin Hall effect of the heavy metal materials. By adjusting the direction of the magnetic moment of the neighboring ferromagnetic layer, the size of the spin current injected into the ferromagnetic layer can be controlled. When the polarization vector of the spin current is perpendicular to the magnetic moment of the neighboring ferromagnetic layer, the spin current will be almost completely absorbed by the ferromagnetic layer; and when the polarization vector of the spin current is collinear with the magnetic moment of the neighboring ferromagnetic layer, most of the spin current will be reflected by the ferromagnetic layer. According to the inverse spin Hall effect, the net spin current in the heavy metal will induce a charge flow in the opposite direction. Therefore, when the polarization vector of the spin current is perpendicular to the neighboring ferromagnetic layer, a larger additional current is generated, and the resistance of the heavy metal layer presents a high resistance state; when the polarization vector of the spin current is parallel to the neighboring ferromagnetic layer, a smaller additional current is generated, and the resistance of the heavy metal layer presents a low resistance state. The resistivity of the heavy metal layer and the magnetic moment direction of the neighboring ferromagnetic layer satisfy the following dependence relationship (1): ; (1) in, is the resistivity that is independent of the direction of the magnetic moment, is the unit magnetic moment vector. SMR was first reported in Pt / yttrium iron garnet (Y3Fe5O 12 , YIG) heterojunctions and was later confirmed in ferromagnetic / heavy metal and antiferromagnetic / heavy metal heterojunctions.

[0004] Ferromagnetic / heavy metal heterojunctions usually exhibit a positive spin Hall magnetoresistance effect. When the ferromagnetic metal exceeds a certain critical thickness, it exhibits a negative spin Hall magnetoresistance effect due to the size effect. Regulating the spin Hall magnetoresistance of ferromagnetic / heavy metal heterojunctions is one of the important research topics in spin electronics.

[0005] At present, there are two main methods for regulating the spin Hall magnetoresistance of ferromagnetic / heavy metal heterojunctions: one is to replace the traditional single-component heavy metal materials by selecting heavy metal alloys with strong spin-orbit coupling effects, and to regulate the alloy composition to optimize the conversion efficiency of the spin current in the heavy metal layer, thereby improving the spin Hall magnetoresistance of the heterojunction. Although this method can improve the conversion efficiency of the spin current, it is very sensitive to the composition of the heavy metal and has a high cost, and it cannot achieve the regulation of the sign of the spin Hall magnetoresistance of the ferromagnetic / heavy metal heterojunction. The other is to regulate the transmission efficiency of the spin current at the ferromagnetic metal / heavy metal interface by inserting an ultra-thin intermediate layer at the ferromagnetic metal / heavy metal interface, thereby achieving the regulation of the spin Hall magnetoresistance. Although this method can achieve the regulation of the sign of the spin Hall magnetoresistance, it cannot effectively improve the spin Hall magnetoresistance of the heterojunction, and this method has actually destroyed the original ferromagnetic / heavy metal interface.

[0006] Therefore, how to regulate the spin Hall magnetoresistance in a heterojunction without changing the heavy metal material and the ferromagnetic / heavy metal interface is one of the major challenges currently facing the field of spin electronics. Summary of the invention

[0007] In view of this, an embodiment of the present invention provides a method for controlling spin Hall magnetoresistance of a ferromagnetic / heavy metal heterojunction to eliminate or improve one or more defects existing in the prior art.

[0008] In one aspect, the present invention provides a method for controlling spin Hall magnetoresistance of a ferromagnetic / heavy metal heterojunction, the method comprising the following steps: The pretreated substrate is placed in a first deposition system chamber, and based on a first preset deposition method, a thin film is deposited on the substrate to form an antiferromagnetic insulating layer; the thickness of the antiferromagnetic insulating layer is controlled by setting deposition parameters, and when the thickness of the antiferromagnetic insulating layer is less than a preset critical thickness, its Né'er vector is perpendicular to the substrate surface, and when the thickness of the antiferromagnetic insulating layer is not less than the preset critical thickness, its Né'er vector is parallel to the substrate surface; The deposited antiferromagnetic insulating layer is transferred to the second deposition system chamber, and based on the second preset deposition method, the epitaxially grown antiferromagnetic insulating layer is used as the bottom layer, and a ferromagnetic metal / heavy metal heterojunction of a preset material is deposited to obtain a multilayer film structure of the antiferromagnetic insulating layer, the ferromagnetic metal layer and the heavy metal layer from bottom to top; By regulating the direction of the Née vector of the antiferromagnetic insulating layer, the reflection and absorption of the ferromagnetic / heavy metal heterojunction spin current are regulated to change the size and sign of the spin Hall magnetoresistance.

[0009] In some embodiments of the present invention, the antiferromagnetic insulating layer adopts antiferromagnetic insulating oxide material, and the antiferromagnetic insulating oxide material includes at least nickel oxide, cobalt oxide, and chromium oxide; the ferromagnetic metal layer adopts magnetic metal material, and the magnetic metal material includes at least cobalt, cobalt-iron-boron alloy, cobalt-iron alloy, and nickel-iron alloy; the heavy metal layer adopts heavy metal material, and the heavy metal material includes at least platinum, tantalum, palladium, gold-platinum alloy, and palladium-platinum alloy.

[0010] In some embodiments of the present invention, the substrate is a magnesium oxide single crystal with a 001 orientation, and the substrate is cleaned to remove possible organic contamination and particles.

[0011] In some embodiments of the present invention, the first preset deposition method includes at least a pulsed laser deposition method, a magnetron sputtering method, and a molecular beam epitaxy method; when the pulsed laser deposition method is used, the method further includes: The pretreated substrate is placed in the first deposition system chamber, and a pulsed laser is used to strike a target material, and the target material is deposited on the substrate to form a thin film as an antiferromagnetic insulating layer; the thickness of the antiferromagnetic insulating layer is controlled by setting the number of pulses of the pulsed laser; The deposition conditions include evacuating the first deposition system chamber to a vacuum state, the repetition frequency of the pulsed laser is 1-5 Hz, the pulse energy is 300-350 mJ, the average power is 280-400 mW, and the voltage is 18-24 kV.

[0012] In some embodiments of the present invention, before transferring the deposited antiferromagnetic insulating layer to the second deposition system chamber, the process further includes: After the laser striking is completed, the transfer is performed after the temperature in the first deposition system chamber cools down naturally to room temperature to ensure the stability of the deposited film.

[0013] In some embodiments of the present invention, the second preset deposition method includes at least a pulsed laser deposition method, a magnetron sputtering method, and a molecular beam epitaxy method; when the magnetron sputtering method is used, the deposition conditions include: The second deposition system chamber was evacuated to a vacuum state with a vacuum degree of 2.0×10 -5 Pa, the deposition temperature is room temperature, argon gas is introduced, and the argon pressure is maintained at 0.4~1.2Pa.

[0014] In some embodiments of the present invention, a multilayer film structure including, from bottom to top, the antiferromagnetic insulating layer, the ferromagnetic metal layer and the heavy metal layer is obtained, including: The thickness of the ferromagnetic metal layer is 0.6-6.5 nm, and the thickness of the heavy metal layer is 1-10 nm.

[0015] In some embodiments of the present invention, after obtaining a multilayer film structure including the antiferromagnetic insulating layer, the ferromagnetic metal layer and the heavy metal layer from bottom to top: The multilayer film results are characterized by using one or more methods of X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy to verify the film, including at least the structure, thickness, and lattice arrangement of the film.

[0016] In some embodiments of the present invention, when the multilayer film structure is obtained and the thickness of the antiferromagnetic insulating layer of the multilayer film structure is less than a preset critical thickness: The multilayer film structure is measured at a temperature of 5K to 400K. At low temperatures, it exhibits negative spin Hall magnetoresistance; as the temperature increases, the spin Hall magnetoresistance changes from negative to positive.

[0017] In some embodiments of the present invention, when the multilayer film structure is obtained and the thickness of the antiferromagnetic insulating layer of the multilayer film structure is not less than a preset critical thickness: The multilayer film structure is measured at a temperature of 5K~400K, and the spin Hall magnetoresistance always remains positive; as the temperature increases, the spin Hall magnetoresistance gradually approaches saturation and tends to be stable when approaching room temperature; when the temperature is further increased to 400K, the spin Hall magnetoresistance decreases.

[0018] The present invention provides a method for regulating spin Hall magnetoresistance of a ferromagnetic / heavy metal heterojunction, comprising: introducing an antiferromagnetic insulating layer between a ferromagnetic metal layer and a substrate without changing the heavy metal material and without destroying the ferromagnetic / heavy metal interface, and regulating the reflection and absorption of the spin current of the ferromagnetic / heavy metal heterojunction by regulating the direction of the Née vector of the antiferromagnetic insulating layer, so as to change the size and sign of the spin Hall magnetoresistance. The method provided by the present invention can regulate both the size and sign of the spin Hall magnetoresistance, and provides important guiding significance for the design of a spin Hall magnetoresistance sensor and a novel magnetic random access memory.

[0019] Additional advantages, purposes, and features of the present invention will be described in part in the following description, and will become apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention may be achieved and obtained by the structures specifically indicated in the specification and the accompanying drawings.

[0020] Those skilled in the art will appreciate that the objectives and advantages that can be achieved with the present invention are not limited to the above specific description, and the above and other objectives that can be achieved by the present invention will be more clearly understood from the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute a limitation of the present invention. In the drawings: Figure 1 Schematic diagram of the steps of a method for controlling spin Hall magnetoresistance of a ferromagnetic / heavy metal heterojunction in one embodiment of the present invention.

[0022] Figure 2 Schematic diagram of the principle of a method for controlling spin Hall magnetoresistance of a ferromagnetic / heavy metal heterojunction in one embodiment of the present invention.

[0023] Figure 3 Graph showing measured data of the corner magnetoresistance of a NiO (thin) / Co / Pt heterojunction at a temperature of 5K to 400K in one embodiment of the present invention.

[0024] Figure 4 Graph showing measured data of the corner magnetoresistance of a NiO (thick) / Co / Pt heterojunction at a temperature of 5K to 400K in one embodiment of the present invention.

[0025] Figure 5 1 is a graph showing the measured data of the corner magnetoresistance of a NiO (zero thickness) / Co / Pt heterojunction at a temperature of 5K to 400K in one embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. Here, the illustrative embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0027] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the solutions according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0028] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0029] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection with an intermediate.

[0030] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0031] It should be emphasized here that the step marks mentioned below are not intended to limit the order of the steps, but it should be understood that the steps can be executed in the order mentioned in the embodiment, or in a different order from the embodiment, or several steps can be executed simultaneously.

[0032] In order to solve the problem that the existing methods for regulating ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance need to change the heavy metal material or destroy the original ferromagnetic / heavy metal interface, the present invention provides a ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance regulation method, without changing the heavy metal material and the ferromagnetic / heavy metal interface, a buffer layer is introduced between the ferromagnetic metal layer and the substrate, and the buffer layer is an oxide insulating material with antiferromagnetic properties, which is called an antiferromagnetic insulating layer in the present invention. Its spin structure can be regulated by substrate stress, local electric field, and spin current. The ferromagnetic / heavy metal spin Hall magnetoresistance can be modulated by regulating the absorption and reflection of the spin current at the interface of the antiferromagnetic insulating layer / ferromagnetic layer. Figure 1 As shown, the method includes the following steps S101-S103: Step S101: placing the pretreated substrate into a first deposition system chamber, and depositing a thin film on the substrate based on a first preset deposition method to form an antiferromagnetic insulating layer. The thickness of the antiferromagnetic insulating layer is controlled by setting deposition parameters, and when the thickness of the antiferromagnetic insulating layer is less than a preset critical thickness, its Né'er vector is perpendicular to the substrate surface, and when the thickness of the antiferromagnetic insulating layer is not less than the preset critical thickness, its Né'er vector is parallel to the substrate surface.

[0033] Step S102: The deposited antiferromagnetic insulating layer is transferred to the second deposition system chamber, and based on the second preset deposition method, the epitaxially grown antiferromagnetic insulating layer is used as the bottom layer, and a ferromagnetic metal / heavy metal heterojunction of a preset material is deposited to obtain a multilayer film structure of an antiferromagnetic insulating layer, a ferromagnetic metal layer and a heavy metal layer from bottom to top.

[0034] Step S103: by regulating the direction of the Née vector of the antiferromagnetic insulating layer, the reflection and absorption of the ferromagnetic / heavy metal heterojunction spin current are regulated to change the size and sign of the spin Hall magnetoresistance.

[0035] In step S101, the substrate is first pre-processed.

[0036] In some embodiments, the substrate is a single crystal of magnesium oxide (MgO) with a 001 orientation, wherein "001 orientation" refers to a specific crystal plane direction of the crystal, and "001" indicates a crystal plane parallel to the z-axis, which is perpendicular to the x-axis and the y-axis.

[0037] In some embodiments, the substrate is cleaned to remove possible organic contaminants and particles. The cleaning method may include using a solvent (such as isopropyl alcohol or acetone) and ultrasonic cleaning.

[0038] Then, the pretreated substrate is placed in a first deposition system chamber, and based on a first preset deposition method, a thin film is deposited on the substrate to form an antiferromagnetic insulating layer.

[0039] In some embodiments, the first preset deposition method includes at least a pulsed laser deposition method, a magnetron sputtering method, and a molecular beam epitaxy method.

[0040] In some embodiments, when pulsed laser deposition (PLD) is used, the pre-treated substrate is placed in a first deposition system chamber, and a pulsed laser is used to strike a target material, which is deposited on the substrate to form a thin film as an antiferromagnetic insulating layer.

[0041] When using the pulsed laser deposition method, the deposition conditions include: evacuating the first deposition system (pulsed laser deposition system) cavity to a vacuum state, and controlling the film quality by setting appropriate deposition parameters, including: the repetition frequency of the pulsed laser is 1~5Hz, the pulse energy is 300~350mJ, the average power is 280~400mW, and the voltage is 18~24kV.

[0042] In some embodiments, the antiferromagnetic insulating layer uses antiferromagnetic insulating oxides such as nickel oxide (NiO), cobalt oxide (CoO) or chromium trioxide (Cr2O3). Taking nickel oxide and pulsed laser deposition as an example, during the deposition process, a pulsed laser is used to strike the nickel oxide target according to pre-set deposition parameters to generate high-energy plasma, and the material in the nickel oxide target evaporates and deposits on the substrate to form a thin film, thereby obtaining an antiferromagnetic insulating layer.

[0043] The thickness of the film (antiferromagnetic insulating layer) is precisely controlled by setting the number of pulses of the pulsed laser. Specifically: for a thinner antiferromagnetic insulating layer (thickness less than the preset critical thickness), due to the stress of the substrate, its Né'er vector (spin direction) will be perpendicular to the substrate surface; while for a thicker antiferromagnetic insulating layer (thickness not less than the preset critical thickness), due to the stress relaxation phenomenon, its Né'er vector tends to be parallel to the substrate surface.

[0044] In step S102, the deposited antiferromagnetic insulating layer is transferred to a second deposition system chamber, and a ferromagnetic metal / heavy metal heterojunction of a preset material is deposited based on a second preset deposition method.

[0045] In some embodiments, step S101 uses a pulsed laser deposition method. After the laser striking is completed, the transfer is performed after the temperature in the pulsed laser deposition system chamber naturally cools down to room temperature to ensure that the deposited film is stable.

[0046] In some embodiments, for the ferromagnetic metal layer, the preset material may be a magnetic metal material such as cobalt (Co), cobalt-iron-boron alloy (CoFeB), cobalt-iron alloy (CoFe) or nickel-iron alloy (NiFe); for the heavy metal layer, the preset material may be a heavy metal material such as platinum (Pt), tantalum (Ta), palladium (Pd), gold-platinum alloy (AuPt) or palladium-platinum alloy (PdPt).

[0047] In some embodiments, the second preset deposition method includes at least pulsed laser deposition, magnetron sputtering, molecular beam epitaxy, etc. When the magnetron sputtering method is used, the deposition conditions include: evacuating the second deposition system (magnetron sputtering coating) chamber to a vacuum state, preferably, the vacuum degree is 2.0×10 -5 Pa, the deposition temperature is room temperature, and the deposition conditions are controlled by adjusting the atmosphere of the sputtering system, such as using argon (Ar) as the atmosphere and controlling the gas pressure of argon to 0.4~1.2Pa.

[0048] In some embodiments, the thickness of the deposited ferromagnetic metal layer is 0.6-6.5 nm, and the thickness of the heavy metal layer is 1-10 nm.

[0049] After the deposition is completed, a multilayer film structure is obtained, which consists of an antiferromagnetic insulating layer, a ferromagnetic metal layer and a heavy metal layer from bottom to top. Taking the antiferromagnetic insulating layer using nickel oxide (NiO) material, the ferromagnetic metal layer using cobalt (Co) material, and the heavy metal layer using platinum (Pt) material as an example, a NiO / Co (ferromagnetic) / Pt (heavy metal) multilayer film heterojunction can be obtained.

[0050] In step S103, the reflection and absorption of the ferromagnetic / heavy metal heterojunction spin current are regulated by regulating the direction of the Née vector of the antiferromagnetic insulating layer to change the magnitude and sign of the spin Hall magnetoresistance.

[0051] For ease of understanding, the principle of the method of the present invention is further explained.

[0052] like Figure 2 As shown in the figure, the multilayer film structure proposed by the present invention includes an antiferromagnetic insulating layer (AFMI), a ferromagnetic metal layer (FMM) and a heavy metal layer (HM) from bottom to top. In (a) and (b), the Née vector of the antiferromagnetic insulating layer is perpendicular to the film plane; in (c) and (d), the Née vector of the antiferromagnetic insulating layer is parallel to the film plane.

[0053] When the Née vector of the antiferromagnetic insulating layer is in the out-of-plane direction, the spin current absorbed at the interface between the ferromagnetic metal layer and the antiferromagnetic insulating layer when the normalized magnetization vector of the ferromagnetic metal layer is parallel to the z-axis is smaller than the spin current absorbed at the interface between the ferromagnetic metal layer and the antiferromagnetic insulating layer when the magnetization vector is parallel to the y-axis. Therefore, the total reflected spin current Satisfies formula (2): (2) in, Indicates heavy metal layer and ferromagnetic metal layer Spin current reflected from the interface; Represents ferromagnetic metal layer and antiferromagnetic insulating layer Spin current reflected from the interface; represents the normalized magnetization vector of the ferromagnetic metal layer; and Respectively, the rectangular coordinate system Axis and axis; Indicates parallelism.

[0054] The net spin current in the heavy metal layer is calculated as shown in formula (3), which satisfies the condition that the magnetization vector is parallel to the z-axis ( ) is smaller than the net spin current when the magnetization vector is parallel to the y-axis ( ) is the net spin current, as shown in formula (4): ; (3) ; (4) in, represents the net spin current in the heavy metal layer; represents the total spin current; and For comments, refer to formula (2).

[0055] According to the inverse spin Hall effect (ISHE), a current in the opposite direction to the external current will be generated in the heavy metal layer, resulting in a negative spin Hall magnetoresistance, as shown in formula (5): ; (5) in, represents the spin Hall magnetoresistance when the magnetization vector is parallel to the z-axis; represents the spin Hall magnetoresistance when the magnetization vector is parallel to the y-axis.

[0056] On the contrary, when the Née vector of the antiferromagnetic insulating layer is in-plane, the total reflected spin current Satisfies formula (6): (6) Net spin current in the heavy metal layer Satisfies formula (7): ; (7) This results in a positive spin Hall magnetoresistance, as shown in formula (8): ; (8) The present invention is further described below with reference to specific embodiments.

[0057] like Figure 3 As shown in the figure, the corner magnetoresistance of the Co / Pt heterojunction generated on the NiO film is measured at a temperature of 5K~400K, where the thickness of the NiO film (antiferromagnetic insulating layer) is 20nm, which is a relatively thin thickness, the thickness of Co (ferromagnetic metal layer) is 1.2nm, and the thickness of Pt (heavy metal layer) is 3nm.

[0058] like Figure 3 As shown, the NiO / Co / Pt multilayer film heterojunction exhibits negative spin Hall magnetoresistance at low temperature, and as the temperature increases, the spin Hall magnetoresistance changes from negative to positive.

[0059] like Figure 4 As shown, the corner magnetoresistance of the Co / Pt heterojunction generated on the NiO film is measured at a temperature of 5K~400K, wherein the thickness of the NiO film (antiferromagnetic insulating layer) is 78nm, which is relatively thick, the thickness of Co (ferromagnetic metal layer) is 1.2nm, and the thickness of Pt (heavy metal layer) is 3nm.

[0060] like Figure 4 As shown in the figure, the spin Hall magnetoresistance of the NiO / Co / Pt multilayer film heterojunction always remains positive; as the temperature increases, the spin Hall magnetoresistance gradually approaches saturation and tends to be stable when approaching room temperature; when the temperature is further increased to 400K, the spin Hall magnetoresistance decreases.

[0061] It can be seen that at low temperatures, the sign of the spin Hall magnetoresistance is mainly regulated by the Née vector of the antiferromagnetic insulating layer NiO. For the antiferromagnetic insulating layer NiO with the Née vector perpendicular to the film, the spin current reflection at the NiO / Co interface is significantly enhanced. As the temperature rises, the modulation effect of the NiO spin orientation on the Co / Pt heterojunction spin Hall magnetoresistance gradually weakens. Therefore, at room temperature, the NiO / Co / Pt heterojunction spin Hall magnetoresistance is mainly determined by the reflection of the spin current at the Co / Pt interface.

[0062] like Figure 5 As shown in the figure, for the Co (1.2 nm) / Pt (3 nm) heterojunction with zero NiO thickness, its spin Hall magnetoresistance gradually approaches saturation and always remains positive as the temperature increases.

[0063] The above results indicate that the spin current transport in the Co / Pt heterojunction can be effectively regulated by regulating the direction of the NiO Néel vector, thereby changing the sign and magnitude of the spin Hall magnetoresistance.

[0064] It should be clear that the present invention is not limited to the specific configuration and processing described above and shown in the figures. For the sake of simplicity, a detailed description of the known method is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0065] In the present invention, features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for controlling spin Hall magnetoresistance of a ferromagnetic / heavy metal heterojunction, characterized in that: The method comprises the following steps: The pretreated substrate is placed in a first deposition system chamber, and based on a first preset deposition method, a thin film is deposited on the substrate to form an antiferromagnetic insulating layer; the thickness of the antiferromagnetic insulating layer is controlled by setting deposition parameters, and when the thickness of the antiferromagnetic insulating layer is less than a preset critical thickness, its Né'er vector is perpendicular to the substrate surface, and when the thickness of the antiferromagnetic insulating layer is not less than the preset critical thickness, its Né'er vector is parallel to the substrate surface; The deposited antiferromagnetic insulating layer is transferred to the second deposition system chamber, and based on the second preset deposition method, the epitaxially grown antiferromagnetic insulating layer is used as the bottom layer, and a ferromagnetic metal / heavy metal heterojunction of a preset material is deposited to obtain a multilayer film structure of the antiferromagnetic insulating layer, the ferromagnetic metal layer and the heavy metal layer from bottom to top; By regulating the direction of the Née vector of the antiferromagnetic insulating layer, the reflection and absorption of the ferromagnetic / heavy metal heterojunction spin current are regulated to change the size and sign of the spin Hall magnetoresistance.

2. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 1, characterized in that: The antiferromagnetic insulating layer is made of antiferromagnetic insulating oxide material, and the antiferromagnetic insulating oxide material includes at least nickel oxide, cobalt oxide, and chromium oxide; the ferromagnetic metal layer is made of magnetic metal material, and the magnetic metal material includes at least cobalt, cobalt-iron-boron alloy, cobalt-iron alloy, and nickel-iron alloy; the heavy metal layer is made of heavy metal material, and the heavy metal material includes at least platinum, tantalum, palladium, gold-platinum alloy, and palladium-platinum alloy.

3. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 1, characterized in that: The substrate is a magnesium oxide single crystal with a 001 orientation, and the substrate is cleaned to remove possible organic pollution and particles.

4. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 1, characterized in that: The first preset deposition method at least includes a pulsed laser deposition method, a magnetron sputtering method, and a molecular beam epitaxy method; When the pulsed laser deposition method is used, the method further comprises: The pretreated substrate is placed in the first deposition system chamber, and a pulsed laser is used to strike a target material, and the target material is deposited on the substrate to form a thin film as an antiferromagnetic insulating layer; the thickness of the antiferromagnetic insulating layer is controlled by setting the number of pulses of the pulsed laser; The deposition conditions include evacuating the first deposition system chamber to a vacuum state, the repetition frequency of the pulsed laser is 1-5 Hz, the pulse energy is 300-350 mJ, the average power is 280-400 mW, and the voltage is 18-24 kV.

5. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 4, characterized in that: Before transferring the deposited antiferromagnetic insulating layer to the second deposition system chamber, the method further includes: After the laser striking is completed, the transfer is performed after the temperature in the first deposition system chamber cools down naturally to room temperature to ensure the stability of the deposited film.

6. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 1, characterized in that: The second preset deposition method at least includes pulsed laser deposition, magnetron sputtering, and molecular beam epitaxy; When the magnetron sputtering method is used, the deposition conditions include: The second deposition system chamber was evacuated to a vacuum state with a vacuum degree of 2.0×10 -5 Pa, the deposition temperature is room temperature, argon gas is introduced, and the argon pressure is maintained at 0.4~1.2Pa.

7. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 1, characterized in that: A multilayer film structure is obtained, which comprises, from bottom to top, the antiferromagnetic insulating layer, the ferromagnetic metal layer and the heavy metal layer, including: The thickness of the ferromagnetic metal layer is 0.6-6.5 nm, and the thickness of the heavy metal layer is 1-10 nm.

8. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 1, characterized in that: After obtaining a multilayer film structure including the antiferromagnetic insulating layer, the ferromagnetic metal layer and the heavy metal layer from bottom to top: The multilayer film results are characterized by using one or more methods of X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy to verify the film, including at least the structure, thickness, and lattice arrangement of the film.

9. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 1, characterized in that: When the multilayer film structure is obtained, and the thickness of the antiferromagnetic insulating layer of the multilayer film structure is less than a preset critical thickness: The multilayer film structure is measured at a temperature of 5K to 400K, and exhibits negative spin Hall magnetoresistance at low temperatures; As the temperature increases, the spin Hall magnetoresistance changes from negative to positive.

10. The ferromagnetic / heavy metal heterojunction spin Hall magnetoresistance control method according to claim 1, characterized in that: When the multilayer film structure is obtained, and the thickness of the antiferromagnetic insulating layer of the multilayer film structure is not less than the preset critical thickness: The multilayer film structure is measured at a temperature of 5K~400K, and the spin Hall magnetoresistance always remains positive; as the temperature increases, the spin Hall magnetoresistance gradually approaches saturation and tends to be stable when approaching room temperature; when the temperature is further increased to 400K, the spin Hall magnetoresistance decreases.

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