Magnetic heterostructure for current-to-spin current conversion, spintronic device and method of fabrication

Abstract

The application provides a magnetic heterojunction structure for current-to-spin current conversion, a spintronic device and a preparation method, and the magnetic heterojunction structure comprises a substrate and a magnetic heterojunction formed on the substrate, the magnetic heterojunction comprises a ferromagnetic layer and a non-magnetic layer, the non-magnetic layer is an alloy layer formed by a material of a group IIIA element in the periodic table and a material of a group VA element; wherein the ferromagnetic layer has perpendicular magnetic anisotropy. The application can utilize the contribution from P-orbital spin current, utilize the prepared high-quality III-V alloy thin film to obtain a high-quality magnetic heterojunction structure, and thus obtain a high-quality electronic device, open up a path for improving spin current efficiency, and further expand the range of materials that can be used for spintronic applications.

Description

Technical Field

[0001] This invention relates to the field of electronic device technology, and in particular to a method for fabricating a magnetic heterojunction, a spintronic device, and a magnetic heterojunction structure for current-spin-current conversion. Background Technology

[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 deflect to opposite edges of the material, generating a transverse spin current. When this spin current is injected into an adjacent ferromagnetic layer, it generates a spin-orbit torque (SOT), which can effectively manipulate the magnetization of the ferromagnetic layer. This current-induced magnetization switching is significant for next-generation memories and logic devices, providing a pathway to non-volatile and energy-efficient data storage technologies.

[0003] To date, traditional SOT materials, such as transition metals like Ta, W, and Pt, rely on strong spin-orbit coupling of d orbitals to generate spin current, converting charge current into spin current and applying it to adjacent ferromagnetic layers, thereby achieving magnetization switching. This characteristic is crucial for reducing operating power and minimizing energy consumption in large-scale integrated circuits. However, how to achieve a more efficient conversion from current to spin current, thereby further improving the performance of devices in integrated circuits, remains a problem that has been continuously researched and is yet to be solved. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a method for fabricating magnetic heterojunctions, spintronic devices, and magnetic heterojunction structures for current-spin-current conversion, in order 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] substrate; and

[0007] A magnetic heterostructure is formed on the substrate, the magnetic heterostructure comprising: a ferromagnetic layer and a non-magnetic layer, wherein the non-magnetic layer is an alloy layer formed of materials of Group IIIA and Group VA elements of the periodic table;

[0008] The ferromagnetic layer has perpendicular magnetic anisotropy.

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

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

[0011] In some embodiments of the present invention, the magnetic heterojunction structure further includes a protective 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, wherein 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 fabricating a magnetic heterojunction structure for current-spin-current conversion. The magnetic heterojunction includes: a substrate and a magnetic heterojunction formed on the substrate. The magnetic heterojunction includes: a ferromagnetic layer and a non-magnetic layer formed on the ferromagnetic layer. The non-magnetic layer is an alloy layer formed of materials of Group IIIA and Group VA elements of the periodic table. The ferromagnetic layer has perpendicular magnetic anisotropy. The method includes the following steps for forming the magnetic heterojunction on the substrate: forming a first film structure on the substrate; and forming a second film structure on the first film structure. In the first and second film structures, one film structure is a ferromagnetic film structure, and the other is a non-magnetic film structure. The non-magnetic film structure is fabricated using a magnetron sputtering process.

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

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

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

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

[0018] In another aspect, the present invention provides a spintronic device for current-to-spin current conversion, the spintronic device comprising a magnetic heterojunction structure for current-to-spin current conversion as described above.

[0019] In some embodiments of the present invention, the spintronic device includes: magnetic storage device, logic operation device, magnetic sensor, quantum computing and quantum storage device, etc.

[0020] The magnetic heterojunction structure, its preparation method, and the spintronic device of the present invention can utilize the contribution from the spin current of the p-orbital to obtain a high-quality magnetic heterojunction structure using the prepared high-quality III-V alloy thin film, thereby obtaining a high-quality spintronic device. This opens up a path to improve spin current efficiency and also expands the range of materials that can be used for spintronics applications.

[0021] Additional advantages, objects, and features of the invention will be set forth in part in the description which follows, and will also become apparent in part to those skilled in the art upon studying the description, or may be learned by practice of the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures specifically pointed out in the description and drawings.

[0022] Those skilled in the art will understand that the objectives and advantages achievable with the present invention are not limited to those specifically described above, and that the above and other objectives achievable with the present invention will become clearer from the following detailed description. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, are not intended to limit the scope of the invention. The components in the drawings are not drawn to scale but are merely illustrative of the principles of the invention. For ease of illustration and description of certain parts of the invention, corresponding portions in the drawings may be enlarged, i.e., may appear larger relative to other components in an exemplary device actually manufactured according to the invention. In the drawings:

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

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

[0026] Figure 3 This is a schematic flowchart of a method for preparing a magnetic heterojunction structure according to an 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 image of a Hall strip made of Co / In2Bi / AlO heterojunction in one embodiment of the present invention.

[0029] Figure 6 This is a comparison diagram of anomalous Hall effect and SOT flip-flop tests of Hall bars made of Pt / Co / Pt structure and Pt / Co / Pt / In2Bi structure in another embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. Here, the illustrative embodiments and descriptions of this invention are used to explain the invention, but are not intended to limit the invention.

[0031] It should also be noted that, in order to avoid obscuring the invention with unnecessary details, only the structures and / or processing steps closely related to the solution according to the invention are shown in the accompanying drawings, while other details that are not closely related to the invention are omitted.

[0032] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, element, step, or component, but does not exclude the presence or addition of one or more other features, elements, steps, or components.

[0033] In the following description, embodiments of the invention will be illustrated with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar parts, or the same or similar steps.

[0034] The inventors of this invention did not follow the traditional research on d-orbital spin current, but instead conducted research on p-orbital spin current. Through research on III-V alloys, the inventors discovered that III-V alloys such as In-Bi are promising new spin current source materials. The charge-to-spin conversion mechanism in these materials originates from the contribution of p-orbitals, rather than the traditional d-orbitals involved in spin current generation typically found in transition metals. Density functional theory (DFT) calculations and molecular beam epitaxy (MBE) growth methods have been used to explore the properties of these alloys. However, despite the high precision of MBE technology, obtaining high-quality In-Bi alloy films has proven difficult due to challenges in film stability and uniformity. In particular, the low melting point and poor film quality of III-V alloys make the preparation of high-quality III-V alloy films and their application to current-to-spin current conversion-based electronic devices an unsolved problem.

[0035] This invention successfully prepared high-quality non-magnetic A x B y Thin films, where A represents materials of Group IIIA elements such as Ga, In, and Tl, and B represents materials of Group VA elements such as As, Sb, and Bi. x B y This refers to an alloy formed from materials of Group IIIA elements and materials of Group VA elements. x and y These represent the component ratios of A and B in the alloy, respectively. Furthermore, based on high-quality non-magnetic A... x B y This invention successfully fabricated a ferromagnetic / nonmagnetic heterojunction using a thin-film fabrication process and successfully detected the conversion of charge to spin current, representing a significant advancement in the exploration of novel spintronic materials. Based on the fabricated heterojunction, this invention also provides a spintronic device incorporating the fabricated heterojunction structure and based on current-spin current conversion.

[0036] As an example, the present invention successfully prepared FM / A x B y An AlO heterojunction was constructed, and a charge-to-spin current conversion was detected within the heterojunction. FM / A x B y In AlO heterojunctions, FM represents ferromagnetic thin films, such as Co, PY alloys (permalloy), and two-dimensional magnetic materials like FeGeTe, etc. x By For example, In x Bi y AlO represents oxide thin films (such as Al2O3, which can be abbreviated as AlO). The inventors discovered that A x B y The charge-to-spin transfer mechanism in A0 metals originates from the contribution of the p-orbitals, rather than the conventional d-orbitals that typically involve spin current generation in transition metals. This introduces a new paradigm to the field of spintronics. Utilizing the contribution from the p-orbital spin current not only paves the way for improving spin current efficiency but also expands the range of materials that can be used for spintronic applications. The inventors' results demonstrate that A0 metals with unique electronic structure and spin transport properties... x B y These materials can serve as fundamental materials for developing next-generation spintronic devices. These results provide a new perspective for the design of low-power, high-efficiency spintronic systems, pushing the boundaries between materials science and device engineering.

[0037] The magnetic heterojunction structure and its preparation method of the present invention will be described in more detail below.

[0038] An embodiment of the present invention provides a magnetic heterojunction structure for current-spin-current conversion, comprising:

[0039] substrate; and

[0040] A magnetic heterostructure formed on a substrate, comprising a ferromagnetic layer and a non-magnetic layer. The non-magnetic layer is an alloy layer formed of materials from Group IIIA and Group VA elements of the periodic table; the ferromagnetic layer exhibits perpendicular magnetic anisotropy.

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

[0042] In embodiments of the present invention, the ferromagnetic layer can be a ferromagnetic monolayer film or a ferromagnetic multilayer film. Examples of ferromagnetic monolayer films include ferromagnetic metal thin films (such as Co metal thin films), ferromagnetic alloy thin films (such as PY alloy thin films), or two-dimensional ferromagnetic material thin films (such as FeGeTe (e.g., Fe3GeTe2 or Fe5GeTe2), Cr2Ge2Te6 or Fe3GaTe2) or other two-dimensional ferromagnetic materials). Ferromagnetic multilayer films may include two or more film layers, which may include metal layers and / or alloy layers, at least one of which is a ferromagnetic layer, such that the multilayer film as a whole is ferromagnetic. Examples of ferromagnetic multilayer films include Pt / Co / Pt. The materials given for the ferromagnetic layer are merely examples, and the present invention is not limited thereto; other known ferromagnetic materials may also be used.

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

[0044] In some embodiments of the present invention, the magnetic heterojunction structure, in addition to including a substrate and a magnetic heterojunction, also includes a protective layer formed on the heterojunction to protect the magnetic heterojunction from oxidation. This protective layer may be aluminum oxide or magnesium oxide, but is not limited to these. 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, with the ferromagnetic layer placed between the two non-magnetic layers to form a sandwich magnetic heterojunction, such as an In5Bi3 / Py / In5Bi3 heterojunction.

[0046] Figure 1 The diagram shown is a schematic representation 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 The AlO heterostructure comprises: a Si / SiO2 substrate, a ferromagnetic (FM) thin film, and a non-magnetic AlO2 layer. x B y Thin film and AlO protective layer. Based on the different group IIIA and VA elements and the material selection of the FM film, the values ​​of x and y are different. The thickness and ratio of each layer structure are selected to enable the ferromagnetic layer as a whole to have good perpendicular magnetic anisotropy. Figure 1 The FM layer shown in the diagram has a thickness of 3 nm, but this thickness is merely an example and the invention is not limited thereto; Ax B y The thickness of the thin film is not given a specific value, but is expressed as t nm. The value of t has a relatively wide range, preferably from a few nanometers to tens of nanometers. The thickness of the AlO film is 3 nm, but this thickness is only an example and the invention is not limited thereto. FM / A x B y The nonmagnetic layer A in the AlO heterostructure x B y The film endows the heterojunction with the ability to convert current into spin current, thereby enabling the verification of A through methods such as spin Hall magnetoresistance measurement (SMR) or terahertz laser testing (THz). x B y Generation of P-orbital spin flow in thin films.

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

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

[0049] Figure 1 FM / A in x B y The preparation process of AlO heterojunction is as follows: Figure 2 As shown. An example of its specific preparation process is as follows:

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

[0051] (2) Place the Si / SiO2 substrate into the magnetron sputtering instrument and wait for the background vacuum to reach the predetermined vacuum level, such as 1E-5 Pa;

[0052] (3) Inert gas, such as argon, is introduced into the magnetron sputtering cavity, and the working gas pressure is adjusted to a specific value. A DC power supply is used to perform magnetron sputtering on the ferromagnetic target material with a certain power to obtain a ferromagnetic film.

[0053] (4) Adjust the working air pressure to a specific value, use a DC power supply, and apply a certain power to A. x B y Magnetron sputtering of alloy targets to grow a specific thickness yields non-magnetic A. x B y membrane;

[0054] Because Group IIIA and Group VA metals have relatively low melting points, it is difficult to form films using the MBE growth method, or the film quality is poor. Therefore, in this embodiment of the invention, in order to improve the melting point of Group III-V metals... x B y The film quality of the alloy was assessed by growing A at room temperature or below using magnetron sputtering. x B y Alloy thin film. Furthermore, to further improve the film quality, in this embodiment of the invention, the magnetron sputtered A film is further processed in an inert gas environment. x B y Perform relaxation processing.

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

[0056] (5) Transfer the film to an inert gas (such as nitrogen) environment for a certain period of time, such as 30 minutes;

[0057] (6) Processes (4) and (5) can be executed only once, or they can be repeated multiple times, i.e., the non-magnetic membrane A can be executed multiple times. x B y The sputtering and relaxation processes can be flexibly set, such as 2-4 times, but the present invention is not limited thereto.

[0058] (7) Adjust the working gas pressure to a specific value, use an RF power supply, and perform magnetron sputtering on the AlO target material at a certain power to grow a protective film of a specific thickness; finally, FM / A is obtained. x B y / AlO heterojunction.

[0059] The following provides a more specific embodiment, which further illustrates the heterojunction preparation process and its characteristics:

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

[0061] (1) The thermally oxidized silicon substrate is adhered to the sample holder and sent into the sputtering chamber of the magnetron sputtering equipment.

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

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

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

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

[0066] (6) Connect the DC power supply to the target cavity where the In2Bi alloy target is located, and adjust the power to 4 W. Open the target cavity baffle and start the ignition sputtering. The sputtering time is 4 min 33 s.

[0067] (7) Turn off the DC power supply and close the target cavity baffle of the In2Bi target. Transfer the thermally oxidized silicon substrate processed in the above steps to the injection chamber. Turn off the molecular pump in the injection chamber, close the insert valve, turn on the nitrogen gas, and open the gas inlet valve of the injection chamber to introduce nitrogen gas. Adjust the gas pressure in the injection chamber to atmospheric pressure. Allow the In2Bi film to relax in the nitrogen atmosphere for 30 min.

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

[0069] (9) Repeat the above process (6)-(8) three times, that is, perform a total of four magnetron sputtering and relaxation processes.

[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 to 50 W, open the target cavity baffle, and start the ignition sputtering. The sputtering time is 2 min 54 s.

[0071] (11) Remove the thermally oxidized silicon substrate to obtain the Co / In2Bi / AlO heterojunction structure.

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

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

[0074] Figure 4 (b) is the AFM image of the Co(3nm) / In2Bi(13 nm) / AlO(3nm) heterojunction prepared by magnetron sputtering and four relaxation processes, with a roughness of Rq=0.942 nm. Figure 4 (a) shows the AFM image of a Co (3 nm) / In₂Bi (13 nm) / AlO (3 nm) heterojunction fabricated solely by magnetron sputtering (without relaxation). Its roughness is Rq = 3.05 nm, indicating a relatively rough surface. The comparison shows that the roughness of the Co / In₂Bi heterojunction grown after multiple relaxations is significantly reduced. Lower roughness results in a smoother interface for the heterojunction, which is beneficial for the subsequent fabrication of Hall bar devices and for exploring the spin Hall effect using Hall bar devices.

[0075] Hall bars were fabricated based on the prepared Co / In₂Bi / AlO heterojunction, and spin Hall magnetoresistance (SHE), anomalous Hall effect, and SOT flip-flop (SOT) tests were performed using these bars. In the spin Hall magnetoresistance test, both the spin Hall effect (SHE) and the inverse spin Hall effect (ISHE) coexist. The spin Hall effect causes the current to be converted into a transverse spin current. Due to the angle between the polarization direction of the non-magnetic layer spin current and the magnetization direction of the adjacent ferromagnetic layer, the magnetic moment of the ferromagnetic layer absorbs or reflects the spin current. The reflected spin current is converted back into a charge current due to the inverse spin Hall effect. Based on this, the magnetoresistance (MR) of the device changes. For example... Figure 5 The image shows the spin Hall magnetoresistance (SMR) test results obtained after fabricating a Hall strip device from a Co (3 nm) / In₂Bi (13 nm) heterojunction. Figure 5 It can be seen that as the device flips in the yz plane, the value of its spin Hall magnetoresistance exhibits a trend that varies with the angle. This trend indicates that a spin current is generated in the Co (3 nm) / In2Bi (13 nm) heterojunction. With terahertz laser emission induced by the inverse spin Hall effect in the heterojunction, a femtosecond laser pulse pumps the heterostructure and generates non-equilibrium spin-polarized electrons in the ferromagnetic layer. Subsequently, these electrons diffuse in the nonmagnetic layer through a superdiffusion process. Due to the inverse spin Hall effect in the nonmagnetic layer, the spin current is then converted into a transient transverse charge current.

[0076] Figure 6The image shown is a comparative test diagram of anomalous Hall effect and SOT flipping of Hall bars made of Pt / Co / Pt structure and Pt / Co / Pt / In2Bi structure in one embodiment of the present invention. Figure 6 (a) shows the anomalous Hall effect and SOT flip test results of the vertical magnetic anisotropy structure Pt / Co / Pt as the FM layer. Figure 6 (b) shows the anomalous Hall and SOT flip test results of the vertical magnetic anisotropy structure Pt / Co / Pt as the FM layer after adding an In2Bi thin film. Figure 6 The results show that the traditional Pt / Co / Pt perpendicular magnetic anisotropy structure, with the addition of an In₂Bi thin film, can achieve switching at a lower current density and with a higher switching ratio. Specifically, the critical switching current density of the Pt / Co / Pt device is 4.80E⁷ A / cm², with a switching ratio of approximately 60%; while the critical switching current density of the Pt / Co / Pt / In₂Bi device is 2.32E⁷ A / cm², with a switching ratio of approximately 82%.

[0077] Furthermore, the Berry curvature of the material can be calculated using existing software such as Wannierberri and Wannier90. Calculations using Wannierberri and Wannier90 revealed that the III-V group alloy material prepared in this invention exhibits a high Berry curvature. This intrinsically high Berry curvature is crucial for the generation of spin currents. Berry curvature can induce spin polarization in electronic states, leading to an imbalance in the spin distribution within the material. When electrons pass through materials with non-flat band structures, 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, thus enabling the conversion of charge current into spin current. It is noteworthy that Berry curvature is an intrinsic property of materials and is not limited to transition metals with strong spin-orbit coupling (SOC). Other materials may also exhibit high Berry curvature, leading to the conversion of current into spin current. The III-V alloy material prepared in this invention has a high Berry curvature, which indicates that this invention has found a current-to-spin current conversion mechanism different from that of traditional transition metals. This mechanism utilizes the contribution from the P-orbital spin current and opens up a path to improve spin current efficiency.

[0078] The magnetic heterojunction structure, its preparation method, and the spintronic device of the present invention can utilize the contribution from the spin current of the p-orbital to obtain a high-quality magnetic heterojunction structure using the prepared high-quality III-V alloy thin film, thereby obtaining a high-quality spintronic device and expanding the range of materials that can be used for spintronics applications.

[0079] In this embodiment of the invention, the non-magnetic layer relaxation atmosphere can be replaced with any gas with stable chemical properties, such as argon or neon. The gas atmosphere used in the preparation steps is not limited to a specific type, as long as it has stable chemical properties.

[0080] Furthermore, in this embodiment of the invention, the temperature during the preparation process can be adjusted. Preferably, magnetron sputtering is used to generate FM thin films at room temperature or under heating conditions, while magnetron sputtering is used to grow A at room temperature or below low temperatures (including but not limited to low temperatures and even ultra-low temperatures). x B y film.

[0081] Furthermore, in this embodiment of the invention, when the FM film is a two-dimensional magnetic material, the FM film can also be prepared without magnetron sputtering. Instead, the two-dimensional magnetic film can be mechanically peeled off and transferred onto a substrate using a material transfer process. In this case, non-magnetic A x B y The thin film and protective layer can still be grown by magnetron sputtering, and A x B y Thin films also utilize relaxation processes to optimize film quality.

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

[0083] Step S110, the step of forming a first film structure on the substrate; and

[0084] Step S120, the step of forming a second film structure on the first film structure, wherein, of the first film structure and the second film structure, one film structure is a ferromagnetic film structure and the other film structure is a nonmagnetic film structure;

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

[0086] The method for preparing vertically magnetically anisotropic thin films / III-V heterojunctions of the present invention involves magnetron sputtering growth at room temperature or low temperature, which can be performed in a single step or in multiple steps with relaxation in an inert atmosphere between the two growths, thus producing high-quality A... x B y Thin film method. This invention achieves for the first time the growth of high-quality III-V alloy thin films using magnetron sputtering, avoiding problems such as poor film quality.

[0087] Based on the above magnetic heterojunction structure, the present invention can fabricate spintronic devices containing magnetic heterojunction structures. These spintronic 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 thereto.

[0088] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are 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. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0089] In this 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 in place of features of other embodiments.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, various modifications and variations of the embodiments of the present invention are possible. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within 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 includes: substrate; and A magnetic heterostructure is formed on the substrate, the magnetic heterostructure comprising: a ferromagnetic layer and a non-magnetic layer, wherein the non-magnetic layer is an alloy layer formed of materials of Group IIIA and Group VA elements of the periodic table; The ferromagnetic layer exhibits perpendicular magnetic anisotropy; the non-magnetic layer is prepared using magnetron sputtering, specifically A, prepared at a set power and at room temperature or below room temperature using magnetron sputtering. x B y Alloy film, where A represents a material of Group IIIA elements and B represents a material of Group VA elements. x and y These represent components A and B, respectively.

2. The magnetic heterojunction structure according to claim 1, characterized in that, The ferromagnetic layer is a single-layer or multi-layer ferromagnetic film. The ferromagnetic monolayer film includes a ferromagnetic metal film, a ferromagnetic alloy film, or a two-dimensional ferromagnetic material film. The ferromagnetic multilayer film includes two or more film layers, the two or more film layers include a metal layer and / or an alloy layer, and at least one of the two or more 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 magnetron sputtering using an alloy target of Group IIIA and Group VA elements at least once, followed by relaxation in an inert gas environment.

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

5. The magnetic heterojunction structure according to claim 1, characterized in that, The magnetic heterojunction structure includes a ferromagnetic layer and two non-magnetic layers, with the ferromagnetic layer placed 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 comprising: a ferromagnetic layer and a non-magnetic layer formed on the ferromagnetic layer, the non-magnetic layer being an alloy layer formed of materials of Group IIIA and Group VA elements of the periodic table; wherein the ferromagnetic layer has perpendicular magnetic anisotropy; the method comprises the following steps for forming the magnetic heterojunction on the substrate, the steps including: The step of forming the first film structure on the substrate; and In the step of forming a second film structure on the first film structure, one film structure is the ferromagnetic layer and the other film structure is the nonmagnetic layer. The non-magnetic layer is prepared using a magnetron sputtering process, wherein the step of preparing the non-magnetic film layer using the magnetron sputtering process includes: a sputtering step, in which A is prepared using a magnetron sputtering process at a set power at a temperature of room temperature or below room temperature. x B y Alloy film, where A represents a material of Group IIIA elements and B represents a material of Group VA elements. x and y These represent components A and B, respectively.

7. The method according to claim 6, characterized in that, The steps for preparing non-magnetic films using magnetron sputtering also include: The relaxation step involves converting the A obtained from the sputtering step into a more stable state. x B y The alloy film relaxes for a predetermined time in an inert gas environment; Repeat the sputtering step and the relaxation step a predetermined number of times.

8. The method according to claim 6, characterized in that, The first film structure is a non-magnetic film structure, the second film structure is a ferromagnetic film structure, and the method further includes: A third film structure is formed on the second film structure using a magnetron sputtering process, wherein the third film structure is a non-magnetic film. The first membrane structure, the second membrane structure, and the third membrane structure form a sandwich-type heterojunction structure.

9. The method according to any one of claims 6-8, characterized in that, The method further includes: A protective layer is formed on the generated magnetic heterojunction using a magnetron sputtering process.

10. The method according to any one of claims 6-8, characterized in that, The ferromagnetic film is a ferromagnetic metal layer or a ferromagnetic alloy layer, and is prepared using a magnetron sputtering process; or The ferromagnetic film is a two-dimensional ferromagnetic material, which is prepared by magnetron sputtering or by mechanical peeling and transfer to a predetermined position.

11. A spintronic device for current-to-spin current conversion, characterized in that, The spintronic device comprises a magnetic heterojunction structure for current-spin-current conversion as described in any one of claims 1-5.

12. The spintronic device according to claim 11, characterized in that, The spintronic devices include: magnetic storage devices, logic operation devices, magnetic sensors, quantum computing devices, and quantum storage devices.

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