Magnetic heterojunction structure for current-spin current conversion, spin electronic device and preparation method

Abstract

The invention provides a magnetic heterojunction structure for current-spin current conversion, a spin electronic device and a preparation method. The magnetic heterojunction structure comprises a substrate, a first electrode, a second electrode, a third electrode and a fourth electrode, the magnetic heterojunction is formed on the substrate, the magnetic heterojunction comprises a ferromagnetic layer and a non-magnetic layer, and the non-magnetic layer is an alloy layer formed by a material of a group IIIA element and a material of a group VA element in a periodic table of elements; wherein the ferromagnetic layer has perpendicular magnetic anisotropy. Compared with the prior art, the method has the advantages that a high-quality magnetic heterojunction structure can be obtained by using the prepared high-quality III-V group alloy film by utilizing the contribution of the spin current from the P orbit, so that a high-quality electronic device is obtained, a way is opened up for improving the spin current efficiency, and the range of materials which can be applied to spintronics is expanded.

Description

Technical Field

[0001] The invention relates to the technical field of electronic devices, and in particular to a magnetic heterojunction for current-spin current conversion, a spin electronic device and a method for preparing a magnetic heterojunction structure. Background Art

[0002] Spin currents can be generated by charge currents in transition metals and can be driven by two well-established mechanisms: the Spin Hall Effect (SHE) and the Rashba-Edelstein Effect (REE). In these mechanisms, charge carriers with opposite spins are deflected to opposite edges of the material, generating a transverse spin current. When this spin current is injected into an adjacent ferromagnetic layer, a spin-orbit torque (SOT) is generated, which can effectively manipulate the magnetization of the ferromagnetic layer. This current-induced magnetization switching is of great significance for next-generation memory and logic devices, providing a path to non-volatile and energy-efficient data storage technologies.

[0003] So far, traditional SOT materials, such as transition metals such as Ta, W and Pt, have relied on strong spin-orbit coupling of d orbitals to generate spin currents, converting charge currents into spin currents and applying them to adjacent ferromagnetic layers, thereby achieving magnetization switching. This feature is of great significance for reducing operating power and minimizing energy consumption in large-scale integrated circuits. However, how to achieve more efficient conversion of current to spin current, thereby further improving the performance of devices in the circuit, is a problem that has been studied and needs to be solved. Summary of the invention

[0004] In view of this, embodiments of the present invention provide a magnetic heterojunction for current-spin current conversion, a spintronic device, and a method for preparing a magnetic heterojunction structure to eliminate or improve one or more defects existing in the prior art.

[0005] One aspect of the present invention provides a magnetic heterojunction for current-spin current conversion, the magnetic heterojunction structure comprising:

[0006] a substrate; and

[0007] A magnetic heterojunction formed on the substrate, the magnetic heterojunction comprising: a ferromagnetic layer and a non-magnetic layer, the non-magnetic layer being an alloy layer formed by a material of a IIIA group element and a material of a VA group element in the periodic table;

[0008] Wherein, the ferromagnetic layer has perpendicular magnetic anisotropy.

[0009] In some embodiments of the present invention, the ferromagnetic layer is a ferromagnetic single-layer film or a multi-layer film; the ferromagnetic single-layer film includes a ferromagnetic metal film, a ferromagnetic alloy film or a two-dimensional ferromagnetic material film; the ferromagnetic multi-layer film includes more than two film layers, the more than two film layers include metal layers and / or alloy layers, and at least one of the more than two film layers is a ferromagnetic layer.

[0010] In some embodiments of the present invention, the non-magnetic layer is obtained by at least once performing magnetron sputtering using an alloy target of a group IIIA element and a group VA element and performing relaxation in an inert gas environment.

[0011] In some embodiments of the present invention, the magnetic heterojunction structure further includes a protection layer formed on the magnetic heterojunction.

[0012] In some embodiments of the present invention, the magnetic heterojunction structure includes: a ferromagnetic layer and two non-magnetic layers, and the ferromagnetic layer is placed between the two non-magnetic layers to form a sandwich magnetic heterojunction.

[0013] Another aspect of the present invention provides a method for preparing a magnetic heterojunction structure for current-spin current conversion, the magnetic heterojunction comprising: a substrate and a magnetic heterojunction formed on the substrate, the magnetic heterojunction comprising: a ferromagnetic layer and a non-magnetic layer formed on the ferromagnetic layer, the non-magnetic layer being an alloy layer formed by materials of elements of Group IIIA and elements of Group VA of the periodic table; wherein the ferromagnetic layer has perpendicular magnetic anisotropy; the method comprises the following steps of forming the magnetic heterojunction on the substrate, the steps comprising: a step of forming a first film layer structure on the substrate; and a step of forming a second film layer structure on the first film layer structure, wherein, of the first film layer structure and the second film layer structure, one film layer structure is a ferromagnetic film layer, and the other film layer structure is a non-magnetic film layer; the non-magnetic film layer is prepared using a magnetron sputtering process.

[0014] In some embodiments of the present invention, the step of preparing the non-magnetic film layer by using the magnetron sputtering process includes: a sputtering step, preparing A by using the magnetron sputtering process at a set power at room temperature or below room temperature. x B y Alloy film layer, wherein A represents a material of Group IIIA elements, B represents a material of Group VA elements, and x and y represent the components of A and B respectively.

[0015] In some embodiments of the present invention, the step of preparing the non-magnetic film layer by using a magnetron sputtering process further includes: a relaxation step of: x B yThe alloy film layer is relaxed for a predetermined time in an inert gas environment; and the sputtering step and the relaxation step are repeated for a predetermined number of times.

[0016] In some embodiments of the present invention, the first film layer structure is a non-magnetic film layer, and the second film layer structure is a ferromagnetic film layer. The method also includes: forming a third film layer structure on the second film layer structure using a magnetron sputtering process, and the third film layer structure is a non-magnetic film layer; the first film layer structure, the second film layer structure and the third film layer structure form a sandwich heterojunction structure.

[0017] In some embodiments of the present invention, the ferromagnetic film layer is a ferromagnetic metal layer or a ferromagnetic alloy layer, and the ferromagnetic film layer is prepared by a magnetron sputtering process; or the ferromagnetic film layer is a two-dimensional ferromagnetic material, and the ferromagnetic film layer is prepared by a magnetron sputtering process or by mechanical peeling and transferring to a predetermined position.

[0018] Another aspect of the present invention provides a spin electronic device for current-spin current conversion, wherein the spin electronic device comprises the magnetic heterojunction structure for current-spin current conversion as described above.

[0019] In some embodiments of the present invention, the spin electronic devices include: magnetic storage devices, logic operation devices, magnetic sensors, quantum computing and quantum storage devices, etc.

[0020] The magnetic heterojunction structure and preparation method thereof and the spin electronic device of the present invention can utilize the contribution from the P orbital spin current and utilize the prepared high-quality III-V alloy film to obtain a high-quality magnetic heterojunction structure, and thus obtain a high-quality spin electronic device, which opens a way to improve the efficiency of spin current and also expands the range of materials that can be used for spin electronic applications.

[0021] 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.

[0022] 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

[0023] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute a limitation of the present invention. The components in the drawings are not drawn to scale, but are only for illustrating the principles of the present invention. In order to facilitate the illustration and description of some parts of the present invention, the corresponding parts in the drawings may be enlarged, that is, they may become larger relative to other components in the exemplary device actually manufactured according to the present invention. In the drawings:

[0024] Figure 1 FM / A in one embodiment of the present invention x B y Schematic diagram of / AlO heterogeneous stacking structure.

[0025] Figure 2 FM / A in one embodiment of the present invention x B y Schematic diagram of the preparation process of / AlO heterojunction.

[0026] Figure 3 Schematic diagram of a process for preparing a magnetic heterojunction structure in one embodiment of the present invention.

[0027] Figure 4 This is a comparison of AFM images of the Co / In2Bi / AlO heterojunction prepared in one embodiment of the present invention.

[0028] Figure 5 This is an SMR test diagram of a Hall bar made of Co / In2Bi / AlO heterojunction in one embodiment of the present invention.

[0029] Figure 6 This is a comparison chart of abnormal Hall and SOT flip tests of Hall bars made of Pt / Co / Pt structure and Pt / Co / Pt / In2Bi structure in another embodiment of the present invention. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] The inventors of the present invention did not follow the traditional research on d-orbital spin flow, but conducted relevant research on P-orbital spin flow. Through the research on III-V alloys, the inventors found that III-V alloy materials such as In-Bi are a promising new type of spin current source material. The charge-to-spin conversion mechanism in these materials comes from the contribution of P orbitals, rather than the traditional d orbitals usually involved in the generation of spin currents in transition metals. Density functional theory (DFT) calculations and molecular beam epitaxy (MBE) growth methods have been used to explore the properties of the alloy. However, although the MBE technology is very accurate, it has been proven difficult to obtain high-quality In-Bi alloy films due to challenges in film stability and uniformity. In particular, III-V alloys have a low melting point and poor film quality. How to prepare high-quality III-V alloy films and use their charge-to-spin conversion mechanism for application in electronic devices based on current-spin current conversion has become an unresolved problem.

[0035] The present invention successfully prepared high-quality non-magnetic A x B y A film, wherein A represents a material of a IIIA group element such as Ga, In, Tl, B represents a material of a VA group element such as As, Sb, Bi, A x B y represents an alloy formed by a material of a Group IIIA element and a material of a Group VA element, and x and y represent the composition ratios of A and B in the alloy, respectively. x B y The present invention successfully prepared a ferromagnetic / non-magnetic heterojunction and successfully detected the conversion of charge to spin current, which is a major progress in the exploration of new spin electronic materials. Based on the prepared heterojunction, the present invention also provides a spin electronic device based on current-spin current conversion including the prepared heterojunction structure.

[0036] As an example, the present invention successfully prepared FM / A x B y / AlO heterojunction, and detected the conversion of charge to spin current in the heterojunction. x B y In the / AlO heterojunction, FM represents a ferromagnetic film, such as Co, PY alloy (Permalloy), two-dimensional magnetic material FeGeTe and other ferromagnetic films, A x B y For example, x Biy , AlO represents an oxide film (such as Al2O3, which can be abbreviated as AlO). The inventors found that A x B y The charge-to-spin conversion mechanism in A comes from the contribution of P orbitals, rather than the traditional d orbitals usually involved in the generation of spin current in transition metals, which introduces a new paradigm in the field of spin electronics. Utilizing the contribution of spin current from P orbitals not only opens a way to improve the efficiency of spin current, but also expands the range of materials that can be used for spin electronics applications. The inventors' research results show that A with unique electronic structure and spin transport properties x B y These results provide new insights into the design of low-power, high-efficiency spintronic systems, pushing the boundaries of materials science and device engineering.

[0037] Next, the magnetic heterojunction structure and the preparation method thereof of the present invention will be described in more detail.

[0038] A magnetic heterojunction structure for current-spin current conversion provided by an embodiment of the present invention includes:

[0039] a substrate; and

[0040] A magnetic heterojunction is formed on a substrate, the magnetic heterojunction comprising: a ferromagnetic layer and a non-magnetic layer. The non-magnetic layer is an alloy layer formed by a material of a IIIA group element and a material of a VA group element in the periodic table; the ferromagnetic layer has perpendicular magnetic anisotropy.

[0041] As an example, the substrate can be a thermally oxidized silicon substrate (Si / SiO2 substrate, i.e., a silicon wafer having a dense silicon dioxide (SiO2) film produced on the surface), but the present invention is not limited thereto and can also be a magnesium oxide (MgO) substrate, an aluminum oxide (Al2O3) substrate or a pure silicon wafer, etc.

[0042] In an embodiment of the present invention, the ferromagnetic layer may be a ferromagnetic single-layer film or a ferromagnetic multilayer film. The ferromagnetic single-layer film is, for example, a ferromagnetic metal film (such as a Co metal film, etc.), a ferromagnetic alloy (such as a PY alloy, etc.) film, or a two-dimensional ferromagnetic material (such as a FeGeTe (such as Fe3GeTe2 or Fe5GeTe2), Cr2Ge2Te6 or Fe3GaTe2) or other two-dimensional ferromagnetic materials, etc.) film. The ferromagnetic multilayer film may include more than two film layers, and the two or more film layers may include metal layers and / or alloy layers, and at least one of the two or more film layers is a ferromagnetic layer, so that the multilayer film is ferromagnetic as a whole. Examples of ferromagnetic multilayer films include Pt / Co / Pt, etc. Here, the material of the ferromagnetic layer is given only as an example, and the present invention is not limited thereto, and it may be other currently known ferromagnetic materials.

[0043] In the embodiment of the present invention, the non-magnetic layer material can be any III-V alloy, such as In2Bi alloy, InBi alloy, In5Bi3 alloy, InGa alloy and AsGa alloy, etc., and can be applied to the same or different spin electronics devices according to the heterojunction structure of different materials.

[0044] In some embodiments of the present invention, the magnetic heterojunction structure includes, in addition to the substrate and the magnetic heterojunction, a protective layer formed on the heterojunction to protect the magnetic heterojunction from oxidation. The protective layer may be aluminum oxide or magnesium oxide, etc., but is not limited thereto. The protective layer may also be omitted.

[0045] In some embodiments of the present invention, the magnetic heterojunction structure can be not only a two-layer structure but also a multi-layer structure. As an example, the magnetic heterojunction structure may include a ferromagnetic layer and two non-magnetic layers, wherein the ferromagnetic layer is disposed between the two non-magnetic layers to form a sandwich magnetic heterojunction, such as an In5Bi3 / Py / In5Bi3 heterojunction.

[0046] Figure 1 FIG. 1 is a schematic diagram of a magnetic heterojunction structure for current-spin current conversion in one embodiment of the present invention. Figure 1 As shown, the magnetic heterojunction structure is FM / A x B y / AlO heterogeneous stacked structure, which includes: Si / SiO2 substrate, ferromagnetic (FM) film, non-magnetic A x B y Based on the selection of different IIIA and VA elements and the material of the FM film, the values ​​of x and y are different, and the thickness and proportion of each layer structure are selected so that the ferromagnetic layer as a whole can have good perpendicular magnetic anisotropy. Figure 1 In the figure, the thickness of the FM layer is shown to be 3 nm, but this thickness is only an example and the present invention is not limited thereto; x B y The thickness of the film is not given a specific value, expressed as t nm, and the value of t has a relatively wide range of values, preferably a few nanometers to tens of nanometers; the thickness of the AlO film layer is 3nm, but this thickness is only an example, and the present invention is not limited to this. FM / A x B y Nonmagnetic layer A in the / AlO heterojunction x B y The film gives the heterojunction the function of converting electric current into spin current, so as to verify A through methods such as spin Hall magnetoresistance measurement (SMR) or terahertz laser testing (THz). x B yGeneration of P orbital spin current in the film.

[0047] In the embodiment of the present invention, the FM film and the non-magnetic A x B y The order between the films is adjustable, that is, the heterogeneous stacked structure FM / A can be obtained by stacking them sequentially on the substrate. x B y / AlO, can also be stacked sequentially to obtain heterogeneous stacking structure A x B y / FM / AlO, in both cases, the magnetic layer and the III-V alloy film A x B y A heterojunction can also be formed.

[0048] In the preparation of the heterojunction of the present invention, the magnetron sputtering technology is mainly used for thin film growth, and FM / A x B y High quality film.

[0049] Figure 1 FM / A x B y The preparation process of / AlO heterojunction is as follows Figure 2 The specific preparation process is as follows:

[0050] (1) Install the target material. The target material may include ferromagnetic target, A x B y Alloy target and AlO target. The ferromagnetic target can be a single ferromagnetic metal target (such as Co target), or an alloy target (such as PY alloy, etc.) or a two-dimensional magnetic material (such as FeGeTe).

[0051] (2) placing the Si / SiO2 substrate into a magnetron sputtering apparatus and waiting for the background vacuum to reach a predetermined vacuum degree, such as 1E-5Pa;

[0052] (3) introducing an inert gas, such as argon, into the magnetron sputtering chamber, adjusting the working gas pressure to a specific value, using a DC power supply, and performing magnetron sputtering on the ferromagnetic target at a certain power to obtain a ferromagnetic film layer;

[0053] (4) Adjust the working gas pressure to a specific value, use a DC power supply, and apply a certain power to A x B y The alloy target is magnetron sputtered to grow a specific thickness to obtain non-magnetic A x B y Membrane layer;

[0054] Since the melting points of group IIIA and group VA metals are relatively low, it is difficult to form a film or the film quality is poor for such low melting point metals by MBE growth. Therefore, in the embodiment of the present invention, in order to improve the melting point of group III-V A x B y The film quality of the alloy is improved by growing A at room temperature or below room temperature using magnetron sputtering. x B y In order to further improve the film quality, in the embodiment of the present invention, the magnetron sputtering growth of A is further carried out in an inert gas environment. x B y Perform relaxation treatment.

[0055] The FM / A x B y The relaxation treatment of the AlO / AlO heterojunction includes the following steps (5):

[0056] (5) transferring the film to an inert gas (e.g., nitrogen) environment and placing it for a certain period of time, such as 30 minutes;

[0057] (6) Process (4) and process (5) can be performed only once, or can be repeated multiple times, that is, the non-magnetic film A can be repeatedly performed multiple times. x B y sputtering process and relaxation process; the number of repetitions can be flexibly set, such as 2-4 times, but the present invention is not limited to this.

[0058] (7) Adjusting the working gas pressure to a specific value, using a radio frequency power supply, magnetron sputtering the AlO target at a certain power to grow a protective film of a specific thickness; finally, FM / A x B y / AlO heterojunction.

[0059] A more specific embodiment is provided below to more specifically illustrate the heterojunction preparation process and characteristics:

[0060] The raw materials involved in the preparation process are: thermally oxidized silicon substrate (Si / SiO2), Co metal target, In2Bi alloy target and Al2O3 oxide target. The preparation process of the heterojunction structure is as follows:

[0061] (1) A thermally oxidized silicon substrate is adhered to a sample holder and placed into the sputtering chamber of a magnetron sputtering device.

[0062] (2) Evacuate the sputtering chamber and wait for the background vacuum of the sputtering chamber to reach 1.0E-5Pa.

[0063] (3) Turn on the argon switch, open the air inlet valve, let argon gas enter the sputtering chamber, and adjust the air pressure in the sputtering chamber to 0.6 Pa by adjusting the molecular pump switch size.

[0064] (4) Connect a DC power supply to the target chamber where the Co metal target is located, and adjust the power to 40 W. Open the target chamber baffle and start sputtering for 27 s.

[0065] (5) Turn off the DC power supply and close the target cavity baffle of the Co target.

[0066] (6) Connect a DC power supply to the target chamber where the In2Bi alloy target is located, adjust the power to 4 W, open the target chamber baffle, and start sputtering for 4 min 33 s.

[0067] (7) Turn off the DC power supply, close the target chamber baffle of the In2Bi target, and transfer the thermally oxidized silicon substrate treated in the above steps to the injection chamber. Turn off the injection chamber molecular pump, close the gate valve, turn on the nitrogen, and open the injection chamber inlet valve to introduce nitrogen, and adjust the injection chamber pressure to atmospheric pressure. Allow the In2Bi film to relax in a nitrogen atmosphere for 30 minutes.

[0068] (8) The relaxed thermally oxidized silicon substrate is sent back into the sputtering chamber, and the background vacuum of the sputtering chamber is waited to reach 3.0E-5Pa.

[0069] (9) The above process (6)-(8) is repeated three times, that is, a total of four magnetron sputtering plus relaxation processes are performed.

[0070] (10) Connect the RF power supply to the target cavity where the Al2O3 oxide target is located, adjust the gas pressure in the sputtering chamber to 0.8 Pa, adjust the RF power supply power to 50 W, open the target cavity baffle, and start sputtering for 2 min 54 s.

[0071] (11) The thermally oxidized silicon substrate is taken out to obtain a Co / In2Bi / AlO heterojunction structure.

[0072] The prepared Co / In2Bi / AlO heterojunction has the following characteristics:

[0073] Co / In2Bi / AlO presents a heterojunction structure, in which the thickness of the Co layer is 3nm, the thickness of In2Bi is 13nm, and the thickness of AlO is 3nm. The overall roughness of the heterojunction is Rq=0.942nm.

[0074] Figure 4 (b) is an AFM image of the Co(3nm) / In2Bi(13nm) / AlO(3nm) heterojunction prepared by magnetron sputtering plus four relaxation processes, with a roughness of Rq=0.942nm. Figure 4(a) is an AFM image of a Co(3nm) / In2Bi(13nm) / AlO(3nm) heterojunction prepared only by magnetron sputtering (without relaxation process), with a roughness of Rq=3.05nm, and a relatively rough surface. By comparison, it can be seen that the roughness of the Co / In2Bi heterojunction after multiple relaxation growths is significantly reduced. The lower roughness leads to a smoother interface of the heterojunction, which is conducive to the subsequent preparation of Hall bar devices and the application of Hall bar devices to the study of the spin Hall effect.

[0075] Hall bars were also made for the prepared Co / In2Bi / AlO heterojunction, and spin Hall magnetoresistance tests, anomalous Hall and SOT flip tests were performed based on the Hall bars. In the spin Hall magnetoresistance test, the spin Hall effect (SHE) and the inverse spin Hall effect (ISHE) will exist at the same time, and the spin Hall effect will cause the current to be converted into a transverse spin current. Through the angle between the polarization direction of the spin current in the non-magnetic layer and the magnetization direction of the adjacent ferromagnetic layer, the magnetic moment of the ferromagnetic layer will absorb or reflect the spin current, and the reflected spin current will be reconverted into charge flow due to the inverse spin Hall effect. Based on this, the magnetoresistance (MR) of the device will change. For example Figure 5 The figure shows the spin Hall magnetoresistance (SMR) test results after the Co(3nm) / In2Bi(13nm) heterojunction was processed into a Hall bar device. Figure 5 It can be seen that as the device is flipped in the yz plane, the value of its spin Hall magnetoresistance shows a trend of changing with angle. This trend indicates that a spin current is generated in the Co(3nm) / In2Bi(13nm) heterojunction. In the case of terahertz laser emission caused by the inverse spin Hall effect in the heterojunction, the femtosecond laser pulse pumps the heterostructure and generates non-equilibrium spin-polarized electrons in the ferromagnetic layer. Subsequently, these electrons diffuse in the non-magnetic layer through a superdiffusion process. Due to the inverse spin Hall effect in the non-magnetic layer, the spin current is then converted into a transient transverse charge current.

[0076] Figure 6 The figure shows the abnormal Hall and SOT flip comparison test diagram of the Hall bar made of Pt / Co / Pt structure and Pt / Co / Pt / In2Bi structure in one embodiment of the present invention, wherein Figure 6 (a) shows the abnormal Hall and SOT flip test results of the perpendicular magnetic anisotropy structure Pt / Co / Pt as the FM layer. Figure 6 (b) shows the anomalous Hall and SOT flip test results of the perpendicular magnetic anisotropy structure Pt / Co / Pt as the FM layer after adding In2Bi film. Figure 6The results show that the traditional Pt / Co / Pt perpendicular magnetic anisotropy structure can achieve flipping at a lower current density and increase the flipping ratio after adding In2Bi film. The specific effect is: the critical flipping current density of the Pt / Co / Pt device is 4.80E7 A / cm 2 , the reversal ratio is about 60%; and the critical reversal current density of the Pt / Co / Pt / In2Bi device is 2.32E7 A / cm 2 , the flip ratio is about 82%.

[0077] In addition, the Berry curvature of the material can be calculated by existing software such as WannierBerri and Wannier90. Through calculations by WannierBerri and Wannier90, it is found that the III-V alloy material prepared in the present invention has a high Berry curvature. The intrinsic high Berry curvature is crucial for the generation of spin currents. Berry curvature can induce spin polarization in the electronic state, resulting in an unbalanced spin distribution inside the material. When electrons pass through a material with a non-flat band structure, their spin states are "bent" by the Berry curvature, resulting in spin polarization. Under the influence of an external electric or magnetic field, the Berry curvature contributes to the generation of spin currents. The direction of these spin currents is related to the direction of electron motion and the sign of the Berry curvature, so that the charge current can be converted into a spin current. It is worth noting that the Berry curvature is an intrinsic property of the material and is not limited to transition metals with strong spin-orbit coupling (SOC). Other materials may also exhibit high Berry curvature, resulting in the conversion of current into spin current. The III-V alloy material prepared in the present invention has a high Berry curvature, which indicates that the present invention has found a current-to-spin current conversion mechanism different from traditional transition metals. This mechanism utilizes the contribution from the P orbital spin current and opens a way to improve the spin current efficiency.

[0078] The magnetic heterojunction structure and preparation method thereof and the spin electronic device of the present invention can utilize the contribution from the P orbital spin current and utilize the prepared high-quality III-V alloy film to obtain a high-quality magnetic heterojunction structure, thereby obtaining a high-quality spin electronic device, thereby expanding the range of materials that can be used in spin electronics applications.

[0079] In the embodiment of the present invention, the non-magnetic layer relaxation atmosphere can be replaced from nitrogen to any gas with stable chemical properties, such as argon, neon, etc. Any gas atmosphere in the preparation step is not limited to a specific type, as long as it has stable chemical properties.

[0080] In addition, in the embodiment of the present invention, the temperature during the preparation process can be adjusted. Preferably, the FM film is formed by magnetron sputtering at room temperature or under heating, and the A film is grown by magnetron sputtering at room temperature or at a low temperature (including but not limited to low temperature or even ultra-low temperature) below room temperature. x B y film.

[0081] In addition, in the embodiment of the present invention, when the FM film is a two-dimensional magnetic material, the FM film may be prepared not by magnetron sputtering, but by mechanically peeling off the two-dimensional magnetic film and transferring the two-dimensional magnetic film to the substrate through a material transfer process. In this case, the non-magnetic A x B y Thin films and protective layers can still be grown by magnetron sputtering, and A x B y The film also utilizes a continuous process to optimize film quality.

[0082] In summary, if Figure 3 As shown, the method for preparing a magnetic heterojunction structure for current-spin current conversion of the present invention comprises the following steps:

[0083] Step S110, forming a first film layer structure on a substrate; and

[0084] Step S120, forming a second film layer structure on the first film layer structure, wherein one of the first film layer structure and the second film layer structure is a ferromagnetic film layer, and the other film layer structure is a non-magnetic film layer;

[0085] The non-magnetic film layer is prepared by using a magnetron sputtering process.

[0086] The preparation method of the perpendicular magnetic anisotropic film / III-V heterojunction of the present invention: magnetron sputtering growth at room temperature or low temperature, single growth, or multiple growth with relaxation in an inert atmosphere between two growths, to prepare high-quality A x B y The present invention realizes the growth of high-quality thin films of III-V alloys using magnetron sputtering for the first time, avoiding problems such as poor film quality.

[0087] Based on the above magnetic heterojunction structure, the present invention can prepare spin electronics devices containing magnetic heterojunction structures. These spin electronics devices may include: magnetic storage devices (such as non-volatile storage devices), logic operation devices, magnetic sensors, quantum computing and quantum storage devices, etc., but the present invention is not limited to this.

[0088] 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.

[0089] 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 or replace features of other embodiments.

[0090] 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 magnetic heterojunction structure for current-spin current conversion, characterized in that: The magnetic heterojunction structure comprises: a substrate; and A magnetic heterojunction formed on the substrate, the magnetic heterojunction comprising: a ferromagnetic layer and a non-magnetic layer, the non-magnetic layer being an alloy layer formed by a material of a IIIA group element and a material of a VA group element in the periodic table; Wherein, the ferromagnetic layer has perpendicular magnetic anisotropy.

2. The magnetic heterojunction structure according to claim 1, characterized in that: The ferromagnetic layer is a ferromagnetic single-layer film or a multi-layer film; The ferromagnetic single-layer film includes a ferromagnetic metal film, a ferromagnetic alloy film or a two-dimensional ferromagnetic material film; The ferromagnetic multilayer film includes more than two film layers, the more than two film layers include metal layers and / or alloy layers, and at least one of the more than two film layers is a ferromagnetic layer.

3. The magnetic heterojunction structure according to claim 1, characterized in that: The non-magnetic layer is obtained by at least once performing magnetron sputtering using an alloy target of a group IIIA element and a group VA element and performing relaxation in an inert gas environment.

4. The magnetic heterojunction structure according to claim 1, characterized in that: The magnetic heterojunction structure further includes a protection layer formed on the magnetic heterojunction.

5. The magnetic heterojunction structure according to claim 1, characterized in that: The magnetic heterojunction structure comprises: a ferromagnetic layer and two non-magnetic layers, wherein the ferromagnetic layer is arranged between the two non-magnetic layers to form a sandwich magnetic heterojunction.

6. A method for preparing a magnetic heterojunction structure for current-spin current conversion, characterized in that: The magnetic heterojunction comprises: a substrate and a magnetic heterojunction formed on the substrate, the magnetic heterojunction comprises: a ferromagnetic layer and a non-magnetic layer formed on the ferromagnetic layer, the non-magnetic layer is an alloy layer formed by a material of a IIIA group element and a material of a VA group element in the periodic table; wherein the ferromagnetic layer has perpendicular magnetic anisotropy; the method comprises the following steps of forming the magnetic heterojunction on the substrate, the steps comprising: forming a first film structure on the substrate; and The step of forming a second film layer structure on the first film layer structure, wherein one of the first film layer structure and the second film layer structure is a ferromagnetic film layer and the other film layer structure is a non-magnetic film layer; The non-magnetic film layer is prepared by using a magnetron sputtering process.

7. The method according to claim 6, characterized in that The steps of preparing the non-magnetic film layer by magnetron sputtering process include: The sputtering step uses a magnetron sputtering process to prepare A at a set power at room temperature or below room temperature. x B y Alloy film layer, wherein A represents a material of Group IIIA elements, B represents a material of Group VA elements, and x and y represent the components of A and B respectively.

8. The method according to claim 7, characterized in that The step of preparing the non-magnetic film layer by using the magnetron sputtering process also includes: The relaxation step is to convert the A obtained in the sputtering step into x B y The alloy film layer is relaxed for a predetermined time in an inert gas environment; The sputtering step and the relaxation step are repeated a predetermined number of times.

9. The method according to claim 6, characterized in that The first film layer structure is a non-magnetic film layer, the second film layer structure is a ferromagnetic film layer, and the method further includes: forming a third film layer structure on the second film layer structure by using a magnetron sputtering process, wherein the third film layer structure is a non-magnetic film layer; The first film layer structure, the second film layer structure and the third film layer structure form a sandwich heterojunction structure.

10. The method according to any one of claims 6 to 9, characterized in that: The method further comprises: A protective layer is formed on the generated magnetic heterojunction by a magnetron sputtering process.

11. The method according to any one of claims 6 to 9, characterized in that: The ferromagnetic film layer is a ferromagnetic metal layer or a ferromagnetic alloy layer, and the ferromagnetic film layer is prepared by a magnetron sputtering process; or The ferromagnetic film layer is a two-dimensional ferromagnetic material, and is prepared by a magnetron sputtering process or by mechanical stripping and transferring to a predetermined position.

12. A current-spin current conversion spin electronic device, characterized in that: The electrical device comprises a magnetic heterojunction structure for current-spin current conversion according to any one of claims 1 to 5.

13. The spintronic device according to claim 12, characterized in that: The spin electronic devices include: magnetic storage devices, logic operation devices, magnetic sensors, quantum computing and quantum storage devices.

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