Superconducting-spin switchable devices and superconducting-spin switching methods

Abstract

The application relates to the technical field of spin electronics devices and quantum information devices, and provides a superconductor-spin switchable device and a superconductor-spin switching method.The device comprises a magnetic layer and a non-magnetic layer; the magnetic layer has perpendicular magnetic anisotropy; and the non-magnetic layer is a layer; the magnetic layer and the non-magnetic layer form a magnetic / non-magnetic heterojunction; under the condition of being lower than a first temperature, the In-Bi-based alloy layer has superconducting characteristics; and under the condition of being higher than the first temperature, the In-Bi-based alloy layer can realize current-spin current conversion.The application can realize a new type of functional material and a device thereof which can exhibit superconducting characteristics and high-efficiency current-spin current conversion capability in the same material system, break through the limitation of separation of traditional superconducting materials and spin materials, and realize integrated and cooperative work of the two.

Description

Technical Field

[0001] This invention relates to the field of spintronic devices and quantum information devices, and in particular to a superconducting-spin switchable device and a superconducting-spin switching method that can realize superconducting function and current-spin current conversion. Background Technology

[0002] The development of spintronics and superconducting electronics currently faces a long-standing core bottleneck: the lack of a functional material capable of simultaneously achieving high-quality superconductivity and stable current-to-spin current conversion within the same material system. Superconducting materials, with their zero resistance and coherent quantum states, have important applications in quantum computing, quantum interconnects, and low-noise detection. While traditional superconducting materials can form a resistance-free state at low temperatures, most lack substantial spin-to-charge conversion capabilities. Their normal-state conductivity is typically weak, their spin response is extremely weak, and they lack spin-orbit coupling (SOC), thus failing to effectively generate the spin Hall effect or achieve efficient conversion of current to spin current. This prevents superconducting materials from being directly used for the generation, detection, or manipulation of spin current, limiting their deep coupling with spintronics.

[0003] On the other hand, traditional spin current source materials used in spintronics, such as strong SOC metals or topological materials like Pt, W, Ta, and Bi₂Se₃, while exhibiting significant spin Hall, inverse spin Hall, or Rashba effects and effectively converting current into spin current or vice versa, do not possess superconductivity. Heavy metals, for example, belong to normal metallic systems, have high resistivity and high energy consumption, and cannot work collaboratively with superconducting devices in the same layer, hindering the deep integration of superconducting electronics and spintronics. Therefore, in existing technologies, spin devices and superconducting devices often rely on different material systems, making unified integration difficult in terms of functionality, fabrication compatibility, and energy loss.

[0004] The fragmentation of this material system has led to the following unresolved problem: there is currently no single material that can simultaneously satisfy the coexistence of spin flow generation and superconductivity. To overcome this problem, the research community has attempted to achieve superconductivity-spin function integration through multilayer material stacking structures, such as introducing additional topological materials, introducing magnetic topological insulators, or introducing heavy metal layers to form a superconducting-heavy metal bilayer structure to integrate superconductivity and spin function. However, these schemes all have significant limitations, such as: (1) requiring multilayer structures, complex fabrication, and high requirements for interface engineering; (2) mismatch in lattice structure, thermal expansion coefficient, and chemical stability of different materials, and interface scattering and defects significantly affect spin transport, thus leading to problems such as complex heterostructures, interface scattering, interlayer diffusion, mismatched stress, and performance weakening caused by scaffolding effect, resulting in limited device spin injection efficiency, unstable performance, poor repeatability, and the introduction of additional energy consumption; (3) spin function and superconductivity belong to different material layers, and their synergistic effect depends on interface efficiency, making it difficult to achieve true "single material dual function".

[0005] Against this backdrop, there is an urgent need for a novel material system that can simultaneously achieve superconductivity and current-spin-current conversion, in order to break through the long-standing material gap between superconducting electronics and spintronics and achieve true functional integration. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a superconducting-spin switchable device, a superconducting-spin switching method, and a superconducting-spin switchable material that can realize superconductivity and current-spin current conversion, so as to eliminate or improve one or more defects existing in the prior art.

[0007] One aspect of the present invention provides a superconducting spin-switching device comprising: a magnetic layer having perpendicular magnetic anisotropy; and a non-magnetic layer being an In-Bi based alloy layer; the magnetic layer and the non-magnetic layer forming a magnetic / non-magnetic heterojunction; the In-Bi based alloy layer exhibiting superconducting properties below a first temperature, and capable of current-to-spin current conversion above the first temperature.

[0008] In some embodiments of the present invention, the atomic ratio of In to Bi in the In–Bi-based alloy layer ranges from 1:1 to 2:1.

[0009] In some embodiments of the present invention, the thickness of the In–Bi-based alloy layer is 1-100 nm.

[0010] In some embodiments of the present invention, the device further includes: a substrate on which the magnetic / non-magnetic heterojunction is formed; and a protective layer formed on the side of the magnetic / non-magnetic heterojunction away from the substrate.

[0011] In some embodiments of the present invention, the magnetic layer is a ferromagnetic layer, which is a two-dimensional magnetic material layer, a magnetic metal layer, a magnetic alloy layer, a multi-metal layer with magnetism, or a tunneling heterostructure.

[0012] In some embodiments of the present invention, the superconducting-spin-switching device is a Holba-based device.

[0013] In some embodiments of the present invention, the superconducting-spin-switching device is a spin valve-based device; the device further includes another magnetic layer formed on the side of the non-magnetic layer opposite to the magnetic layer.

[0014] In some embodiments of the present invention, the superconducting spin-switching device is a device based on a Josephson junction; the device further includes a superconducting layer formed on the side of the magnetic layer opposite to the non-magnetic layer.

[0015] In some embodiments of this application, the superconducting-spin-switchable device is a superconducting-spin magnetoresistive device, a logic gate device, or a quantum device.

[0016] In some embodiments of the present invention, the In–Bi-based alloy layer includes: InBi, In5Bi3, In2Bi, InBiSn or InBiTe.

[0017] In some embodiments of the present invention, the superconducting-spin switchable device is a multi-channel structure used to measure Hall voltage, resistance, spin Hall magnetoresistance (SMR), and harmonic voltage respectively.

[0018] Another aspect of the present invention provides a superconducting-spin-switching method, which is based on the superconducting-spin-switching device as described above.

[0019] Another aspect of the present invention provides a superconducting spin-switching material, wherein the superconducting spin-switching material is an In–Bi-based alloy material, and the In–Bi-based alloy material is used as a non-magnetic layer in a magnetic / non-magnetic heterojunction in a superconducting spin-switching device as described above.

[0020] The In-Bi-based alloy proposed in this invention possesses a considerable superconducting critical temperature and exhibits a significant and stably measurable spin Hall effect and / or inverse spin Hall effect in its normal state. Its current-to-spin current conversion capability can be clearly verified through spin Hall magnetoresistance and current-driven second harmonic generation tests. This material allows superconductivity and spin current generation to coexist naturally in a single material system, without the need for additional strong SOC metals, topological materials, or complex heterostructures, thus fundamentally solving the aforementioned technical challenges.

[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 This is a schematic diagram of the main structure of a superconducting-spin-switching device in one embodiment of the present invention.

[0025] Figure 2 This is a schematic diagram of the main structure of a superconducting-spin-switching device in another embodiment of the present invention.

[0026] Figure 3 This is a schematic diagram of the structure and testing of the Holba in one embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the structure of a spin valve in one embodiment of the present invention.

[0028] Figure 5 This is a schematic diagram of the Josephson junction in one embodiment of the present invention.

[0029] Figure 6 The resistance-temperature (RT) curve of the In2Bi alloy prepared in one embodiment of the present invention is shown.

[0030] Figure 7 The RT curves of the In2Bi alloy prepared in one embodiment of the present invention under different external magnetic fields are shown.

[0031] Figure 8 This is a schematic diagram of the FC-ZFC (Field-Cooled-Zero-Field-Cooled) magnetization curve of the In2Bi alloy prepared in one embodiment of the present invention.

[0032] Figure 9 This is a schematic diagram of the SMR and fitting curves of Co / In2Bi(t) / Al2O3 devices of different thicknesses at different temperatures in one embodiment of the present invention.

[0033] Figure 10 This presents the test results and fitting data on the second harmonic angle dependence of a Co / In2Bi / Al2O3 device at room temperature in one embodiment of the present invention.

[0034] Figure 11 The results of anomalous Hall effect testing of a FeGaTe / In2Bi / Al2O3 device near temperature Tc in one embodiment of the present invention are shown.

[0035] Figure 12 The results of anomalous Hall effect testing of the FeGaTe / In2Bi / Al2O3 device at a Tc temperature (1.8K) in one embodiment of the present invention are shown.

[0036] Figure 13 This is a diagram showing the Hall resistance of a FeGaTe / In2Bi / Al2O3 device at a temperature Tc (1.8K) and the correspondence between the Hall resistance and the external magnetic field in one embodiment of the present invention.

[0037] Figure 14 This is a spin-orbit torque (SOT) flipping test diagram of a FeGaTe / In2Bi device at room temperature (300K) in one embodiment of the present invention. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] 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.

[0041] It should also be noted that, unless otherwise specified, the term "connection" in this article can refer not only to a direct connection, but also to an indirect connection involving an intermediary.

[0042] With the rapid development of spintronics and quantum technology, how to achieve efficient charge-spin conversion, spin current transport, and low-energy superconductivity in the same material system has become a key scientific problem and technological bottleneck for next-generation information devices. From the perspectives of system performance, device architecture, and energy efficiency, there is an urgent need for a new type of functional material that simultaneously possesses superconductivity and strong spin response capabilities in a single material system, in order to break through the limitations of traditional multilayer heterostructures.

[0043] As described in the background section, traditional methods for integrating superconductivity and spin generally rely on a heterogeneous structure of "superconducting layer + spin functional layer." This not only results in complex structures, limited energy efficiency, and prominent interface problems, but also makes it difficult to obtain a unified material system that can simultaneously optimize superconductivity and spin functionality. Therefore, there is an urgent need for a novel material and corresponding device that can simultaneously exhibit superconducting phase transition and current-spin current conversion capabilities in a single thin film, thereby realizing a truly superconducting-spin dual-functional material platform and solving the core bottleneck of existing technologies.

[0044] To overcome the problems existing in the prior art, this invention, based on the aforementioned technical background, addresses key bottlenecks by proposing an In-Bi based alloy material capable of achieving superconducting-spin switching, a method for achieving superconducting-spin switching based on the In-Bi based alloy, and a superconducting-spin switchable device based on the In-Bi based alloy. Here, the In-Bi based alloy refers to an alloy material containing at least In and Bi. It can contain only In and Bi, or it can contain other metal elements in addition to In and Bi. That is, the In-Bi based alloy as the non-magnetic layer material can be an In-Bi alloy with no other metal elements or with other metal elements in any proportion. This invention uses the In-Bi based alloy material as the functional core for realizing the superconducting-spin switching device. Its uniqueness lies in its ability to simultaneously achieve low-temperature superconductivity and efficient current-spin current conversion capability.

[0045] Figure 1 This is a schematic diagram of the main structure of a superconducting-spin-switching device according to an embodiment of the present invention, as shown below. Figure 1 As shown, the superconducting-spin-switching device includes:

[0046] Magnetic layer 20, the magnetic layer having perpendicular magnetic anisotropy; and

[0047] Non-magnetic layer 10, wherein the non-magnetic layer is an In-Bi based alloy layer, or an In-Bi based alloy thin film;

[0048] The magnetic layer and the non-magnetic layer form a heterojunction; the In-Bi based alloy layer exhibits superconducting properties at temperatures below the first temperature (i.e., the superconducting critical temperature Tc), and at temperatures above the first temperature, the In-Bi based alloy layer can achieve current-spin current conversion.

[0049] In some embodiments of the present invention, the basic structure of the superconducting-spin-switching device adopts a layered structure, with an In-Bi based alloy layer (i.e., the core functional layer) as the core. Magnetic layers with perpendicular magnetic anisotropy, such as ferromagnetic (FM) or antiferromagnetic (AMF) layers, can be deposited on or below the In-Bi based alloy functional layer as needed. The magnetic layer and the In-Bi based alloy layer form a heterojunction. Preferably, the heterojunction can be formed on a substrate, which can be a thermally oxidized silicon substrate (Si / SiO2) or other suitable materials for use as a substrate; the present invention is not limited thereto. In another embodiment of the present invention, a protective layer is also formed on the magnetic / non-magnetic heterojunction to protect the heterojunction. When the superconducting-spin-switching device has both a substrate and a protective layer, the protective layer can be formed on the side of the heterojunction away from the substrate. As examples, typical device configurations may include the following: substrate / FM layer / In-Bi based alloy layer; substrate / In-Bi based alloy layer / FM layer; FM layer / In-Bi based alloy layer / protective layer; In-Bi based alloy layer / FM layer / protective layer; substrate / FM layer / In-Bi based alloy layer / protective layer; substrate / In-Bi based alloy layer / FM layer / protective layer, etc. These structures are merely examples and are not intended to limit the invention.

[0050] In embodiments of the present invention, the atomic ratio of In to Bi in the In-Bi based alloy layer can be arbitrary in principle, but preferably, the atomic ratio of In to Bi in the In-Bi based alloy layer is in the range of 1:1 to 2:1. In and Bi can form stable alloy phases including InBi, In5Bi3, and In2Bi, that is, when the atomic ratio of In to Bi is 1:1, 5:3, or 2:1, alloy phases InBi, In5Bi3, and In2Bi can be formed respectively. When the atomic ratio of In to Bi is between 1:1 and 5:3, alloy phases InBi and In5Bi3 will coexist in the In-Bi based alloy layer; when the atomic ratio of In to Bi is between 5:3 and 2:1, alloy phases In5Bi3 and In2Bi will coexist in the In-Bi based alloy layer; when the atomic ratio of In to Bi is less than 1:1, alloy phase InBi, as well as bismuth-rich solid solution or elemental Bi phase, will coexist in the In-Bi based alloy layer. When the atomic ratio of In to Bi is greater than 2:1, the In–Bi-based alloy layer will simultaneously contain the alloy phase In2Bi and the indium-rich solid solution or elemental indium phase.

[0051] As an example, the In–Bi-based alloy can be selected from InBi, In5Bi3, In2Bi, InBiSn, and InBiTe, etc. Depending on the In / Bi ratio and the doping elements, the heterojunction structure can be applied to different types of superconducting-spin-switching devices. The inventors of this application have discovered that the performance of the superconducting critical temperature (Tc) and spin Hall angle (θ_SH) can be optimized by adjusting the composition ratio in the In–Bi-based alloy layer. Therefore, depending on the In / Bi ratio and the doping elements used, the heterojunction structure can be applied to the study of different forms of spintronics and superconducting properties.

[0052] In a preferred embodiment of this application, the thickness of the In–Bi-based alloy thin film is 1-100 nm, and the In–Bi-based alloy thin film can be prepared by magnetron sputtering.

[0053] To simplify the explanation, we will focus on the structure and fabrication of the device using the FM layer as an example. The case is similar when the magnetic layer is AMF.

[0054] In some embodiments of the present application, the FM layer can be any magnetic metal layer, alloy layer or heterojunction with perpendicular magnetic anisotropy. More specifically, it can be a two-dimensional magnetic material layer, a magnetic alloy thin film, a multi-layer metal thin film with overall magnetism, or a tunneling heterojunction, etc. For example, the two-dimensional magnetic material layer can be FeGaTe, FeGeTe or CrGeTe, etc. Among them, FeGaTe represents a ternary compound of Fe-Ga-Te, such as Fe3GaTe2, etc.; FeGeTe represents a ternary compound of Fe-Ge-Te, such as Fe3GeTe2 or Fe5GeTe2, etc.; CrGeTe represents a ternary compound of Cr-Ge-Te, such as Cr2Ge2Te6, etc. The multi-layer metal thin film with overall magnetism is, for example, a Co / Ni multi-layer film, etc.; the tunneling heterojunction is, for example, a MgO / CoFeB heterojunction, etc. These magnetic materials are only examples, and the present invention is not limited thereto. In practice, the materials of the magnetic layer are not limited to specific types, as long as they are magnetic layers with perpendicular magnetic anisotropy.

[0055] In the functional design of the superconducting-spin switchable device of the present invention, under low-temperature (T < Tc) conditions, the In–Bi-based alloy layer exhibits superconducting characteristics and can be used as a superconducting switch, a low-power consumption quantum transmission channel, etc. Under normal-state (T > Tc) conditions, the In–Bi-based alloy layer can achieve current-spin current conversion, generating spin injection or output, which can be detected through the adjacent FM layer. Therefore, in the embodiments of the present invention, the superconducting-spin switchable device can achieve dual-functional collaborative switching: the superconducting characteristics and the spin current conversion coexist naturally in the same material without additional heavy metal layers or spin source layers. At low temperature, the device presents a zero-resistance state (superconducting state), and at the same time, it can maintain stable spin current generation and detection functions in the normal state, achieving function superposition.

[0056] The Figure 1 The basic structure of the superconducting-spin switchable device shown can be designed as a hall bar, a spin valve, or a Josephson junction, etc., which are basic functional units. For different basic functional units such as hall bars, spin valves, or Josephson junctions, in addition to Figure 1 the structure shown, other layers can also be included. Basic functional units such as hall bars, spin valves, or Josephson junctions can be further integrated to obtain Hall effect sensors / sensor arrays, magnetic storage devices, quantum bit devices, quantum computing devices, encryption devices, and / or reconfigurable logic devices, etc.

[0057] In this application, various devices based on the Hall bar structure can be collectively referred to as Hall bar devices, such as spin-orbit torque magnetic random access memory (SOT-MRAM), Hall quantum devices, and high-performance magnetic sensor devices; various devices based on the spin valve structure can be collectively referred to as spin valve devices, such as hard disk drive read head devices, non-volatile memory, and other spin magnetoresistive devices; various devices based on the Josephson junction can be collectively referred to as Josephson junction devices, such as superconducting diodes and other logic gate devices or superconducting quantum interference devices.

[0058] Figure 3 The diagram shown illustrates a Hall bar device structure and testing schematic based on an FM / In2Bi heterojunction according to an embodiment of the present invention. Hall bars typically employ a long strip or cross-shaped design, with the main current direction (…) Figure 3 Power supply electrodes (source and drain) are set at both ends of the sample in the x-direction, and Hall voltage detection electrodes are symmetrically distributed on the side of the sample. Figure 3 The middle FM layer exhibits perpendicular magnetic anisotropy. Electrodes connected to both ends along the long axis of the device are used for input or output drive current (as shown by I in the figure). xx The electrodes on both sides of the short axis of the device can be used to measure the Hall voltage (V in the figure) generated by the vertical magnetic field H. xy ( ), used to measure the Hall resistance of materials. Figure 3 The voltage V in xx Used to represent the voltage drop along the sample length (source-drain direction), used to measure the bulk conductivity of the material, and reflects the material's resistive properties.

[0059] In some embodiments of the present invention, the basic structure of the spin valve is as follows: Figure 4 As shown, this is a sandwich structure consisting of two magnetic layers sandwiching a non-magnetic layer. The non-magnetic layer 10 is an In-Bi based alloy layer sandwiched between the two magnetic layers. Both magnetic layers are ferromagnetic and exhibit perpendicular magnetic anisotropy. One magnetic layer 20 is used as a reference layer or pinned layer, while the other magnetic layer 50 is used as a free layer. In other words, the spin valve includes... Figure 1 In addition to the heterojunction structure, this heterojunction structure has magnetic layers on both sides of the non-magnetic layer. The spin valve can utilize the giant magnetoresistance (GMR) effect to achieve a low-resistance state when the magnetization directions of the two ferromagnetic layers are parallel, and a high-resistance state when they are antiparallel. The dual-resistance state mechanism of the spin valve is the same as that of existing technologies. In addition, it can achieve a zero-resistance state due to superconductivity when the temperature is below the superconducting critical temperature Tc. Based on the spin valve structure with three resistance states in this invention, it can be used to indicate three states, thereby realizing multi-state storage or information encryption, quantum computing, etc.

[0060] In some embodiments of the present invention, the basic structure of the Josephson knot is as follows: Figure 5As shown, it includes two superconducting layers capable of superconducting properties and a magnetic layer 20 sandwiched between the two superconducting layers. This magnetic layer is a ferromagnetic layer with perpendicular magnetic anisotropy. Both superconducting layers can be In-Bi based alloy layers, or only one superconducting layer can be an In-Bi based alloy layer (i.e., Figure 1 The corresponding non-magnetic layer 10), and the other superconducting layer 60 are conventional superconducting material layers. That is, the Josephson junction includes, in addition to, a non-magnetic layer 10, and a conventional superconducting material layer 60. Figure 1 In addition to the heterojunction structure, a superconducting layer is formed on the other side of the ferromagnetic layer in this heterojunction structure. The Josephson junction, based on the Josephson effect, is the foundation of various electronic devices such as superconducting quantum interference devices (SQUIDs), superconducting qubits, and voltage references. In this embodiment of the invention, besides relying on the Josephson effect, a heterojunction can also be formed between the ferromagnetic layer and the In-Bi based alloy layer at temperatures above the superconducting critical temperature of the superconducting layer, enabling current-to-spin current conversion. Therefore, the Josephson junction based on this invention can also achieve the synergistic operation of superconductivity and spin current conversion, thereby obtaining various devices with dual-function synergy.

[0061] In this embodiment of the invention, the mechanism for the dual-function coordinated switching of the superconducting-spin-switchable device may include: switching from a local or global superconducting state to a spin-current functional state by adjusting the current; changing the critical field of the superconducting material by using an external magnetic field to switch from the superconducting state to the normal state, thus achieving state control; and precisely achieving the superconducting-normal state switching by controlling the local or global material temperature. That is, current and magnetic fields can adjust the superconducting critical temperature to a certain extent. Therefore, multiple control methods can be combined in the same device, improving switching flexibility and safety.

[0062] Furthermore, in some embodiments of the present invention, the superconducting-spin-switching device can also be designed as a multi-channel structure, for example, it can be used to accurately measure Hall voltage, resistance, spin Hall magnetoresistive (SMR) signal, and harmonic voltage, etc. Multiple channels can be achieved through multiple pairs of measuring electrodes positioned appropriately.

[0063] The following describes the fabrication and testing performance of some superconducting spin-switched devices according to some embodiments of the present invention.

[0064] Example 1: The device structure includes a substrate / FM layer / In-Bi based alloy layer / protective layer, wherein the substrate is a Si / SiO2 substrate, the FM layer is a two-dimensional material FeGaTe, the In-Bi based alloy layer is In2Bi, and the protective layer is Al2O3. The FM layer / In-Bi based alloy layer / protective layer form an FeGaTe / In2Bi / Al2O3 heterojunction.

[0065] The raw materials involved in the preparation process are: thermally oxidized silicon substrate (Si / SiO2), FeGaTe two-dimensional material, In2Bi alloy target and Al2O3 oxide target.

[0066] In the preparation of FeGaTe / In2Bi / Al2O3 heterojunctions, two-dimensional dry transfer technology and magnetron sputtering technology are mainly used. The main active component is the FeGaTe / In2Bi heterojunction.

[0067] More specifically, the preparation process of the FeGaTe / In2Bi / Al2O3 heterojunction is as follows:

[0068] (1) The FeGaTe two-dimensional material was transferred to the Si / SiO2 substrate in the glove box by dry transfer technology, and then the Si / SiO2 substrate was removed.

[0069] Dry transfer technology is a mature technology and will not be elaborated on here.

[0070] (2) Place the Si / SiO2 substrate with FeGaTe transferred into the sputtering chamber of the magnetron sputtering equipment and evacuate the sputtering chamber to make the background vacuum reach a certain value, such as 1E-5 Pa. This vacuum value is only an example.

[0071] (3) Argon gas is introduced into the magnetron sputtering chamber and the working gas pressure is adjusted to a certain value, for example, the gas pressure in the sputtering chamber reaches 0.6-1.5 Pa (for example only); then a DC power supply is used to perform magnetron sputtering on the In2Bi alloy target at a certain power (e.g., 2-10W, for example only). The thickness of the growth is controlled by controlling the sputtering power and sputtering time, thereby growing an In2Bi thin film of a specific thickness.

[0072] As an example, by opening the target cavity baffle of the In2Bi alloy target, sputtering can be performed for 13 minutes at a sputtering power of 10W under room temperature conditions, resulting in the growth of an In2Bi film with a thickness of 80nm. Then, the DC power supply is turned off, and the target cavity baffle of the In2Bi alloy target is closed.

[0073] (4) Adjust the working gas pressure to a certain value, use radio frequency power supply, and magnetron sputter the Al2O3 target material with a certain power. The growth thickness can be controlled by controlling the sputtering power and sputtering time, so as to grow an Al2O3 film of a specific thickness.

[0074] As an example, the RF power supply can be connected to the target cavity where the Al2O3 oxide target is located, the sputtering chamber pressure can be adjusted to 0.8Pa, the RF power supply power can be adjusted to 50W, the target cavity baffle can be opened, and the start-up sputtering can be started. The sputtering time is 2 min 54 s.

[0075] The thermally oxidized silicon substrate is removed, thereby obtaining the FeGaTe / In2Bi / Al2O3 heterojunction formed on the thermally oxidized silicon substrate.

[0076] In the above preparation process, the preparation parameters (such as sputtering pressure, sputtering time, sputtering power, substrate temperature, etc.) can be adjusted, as long as the desired structure can be prepared.

[0077] Example 2: The device structure includes a substrate / FM layer / In-Bi based alloy layer, wherein the substrate is a Si / SiO2 substrate, the FM layer is a Pt / Co / Pt multilayer thin film, the In-Bi based alloy layer is In2Bi, and the FM layer / In-Bi based alloy layer is a Pt / Co / Pt / In2Bi heterojunction.

[0078] The raw materials involved in the preparation process are: thermally oxidized silicon substrate (Si / SiO2), Pt metal target, Co metal target, In2Bi alloy target and Al2O3 oxide target.

[0079] The preparation process of Pt / Co / Pt / In2Bi heterojunction is illustrated below:

[0080] (1) The thermally oxidized silicon substrate is adhered to the sample holder, placed in the sputtering chamber of the magnetron sputtering equipment, and the sputtering chamber is evacuated to make the background vacuum of the sputtering chamber reach 1.0 E-5 Pa.

[0081] (2) Argon gas is introduced into the magnetron sputtering chamber and the working gas pressure is adjusted to a certain value, for example, the gas pressure in the sputtering chamber is 0.6-1.5 Pa (for example only).

[0082] (3) Connect the DC power supply to the target cavity where the Pt metal target is located, and adjust the power to a certain value to perform magnetron sputtering of Pt to obtain a Pt thin film of a certain thickness.

[0083] For example, by opening the target cavity baffle of the Pt metal target, controlling the sputtering power to 15 W and the sputtering time to 23 s, a Pt film with a thickness of 2 nm can be grown. Then, the DC power supply is turned off, and the target cavity baffle of the Pt metal target is closed.

[0084] (4) Connect the DC power supply to the target cavity where the Co metal target is located, and adjust the power to a certain value to perform magnetron sputtering of Co to obtain a Co thin film of a certain thickness.

[0085] For example, by opening the target cavity baffle of the Co metal target, controlling the power to 40 W, and setting the sputtering time to 7 s, a Co film with a thickness of 0.8 nm can be grown. Then, the DC power supply is turned off, and the target cavity baffle of the Co metal target is closed.

[0086] (5) Connect the DC power supply to the target cavity where the Pt metal target is located, and adjust the power to a certain value to perform magnetron sputtering of Pt to obtain a Pt thin film of a certain thickness.

[0087] For example, by opening the target cavity baffle of the Pt metal target, controlling the sputtering power to 15 W and the sputtering time to 45 s, a Pt film with a thickness of 4 nm can be grown. Then, the DC power supply is turned off, and the target cavity baffle of the Pt metal target is closed.

[0088] (6) Use a DC power supply to perform magnetron sputtering on the In2Bi alloy target at a certain power (e.g., 2-10W, just an example). Control the thickness of the growth by controlling the sputtering power and sputtering time, thereby growing an In2Bi thin film of a specific thickness.

[0089] For example, by connecting a DC power supply to the target cavity containing the In2Bi alloy target and adjusting the power to 10W, opening the target cavity baffle, and starting spark sputtering for 13 minutes, an In2Bi film with a thickness of 80 nm can be grown. Then, the DC power supply is turned off, and the target cavity baffle of the In2Bi target is closed.

[0090] By removing the thermally oxidized silicon substrate, a Pt / Co / Pt / In2Bi heterojunction can be formed.

[0091] Furthermore, after the In2Bi thin film, a protective layer, such as an Al2O3 thin film, can be grown by magnetron sputtering, thereby obtaining a device structure substrate / FM layer / In–Bi-based alloy layer / protective layer.

[0092] By using similar processes, the atomic ratio of In and Bi in the In-Bi alloy in the non-magnetic layer and the materials of other layers can be changed, and / or other layers can be added, to obtain different basic structures of superconducting-spin-switching devices.

[0093] Figure 6 The figure shows the resistance-temperature (RT) curve of the In2Bi alloy in a Holba device according to an embodiment of this application. As can be seen from the figure, the resistance of the In2Bi alloy in the device drops sharply to 0 at a temperature of 5.8 K, which is one of the most significant characteristics of superconductivity, indicating that superconducting properties have appeared.

[0094] Figure 7 The figure shows the RT curves of the In2Bi alloy prepared in one embodiment of the present invention under different external magnetic fields. Figure 7 As shown, the superconducting critical temperature Tc changes with the strength of the external magnetic field, which is a significant characteristic of type II superconductors. As the external magnetic field strength increases, Tc... c The temperature is gradually reduced until it exceeds the upper critical field (H). c2 (0)), the superconductor loses its superconducting properties.

[0095] Figure 8 The figure shown is a schematic diagram of the FC-ZFC (Field-Cooled-Zero-Field-Cooled) magnetization curve of the In2Bi alloy prepared in one embodiment of the present invention. Figure 8 As shown, the Meissner effect occurs, and the bifurcation between the field cooling curve and the zero field cooling curve occurs at 5.8 K, which is consistent with the temperature at which the RT curve drops sharply. This is also one of the phenomena that prove the occurrence of superconductivity.

[0096] The In-Bi-based alloy proposed in this invention possesses a considerable superconducting critical temperature and exhibits a significant and stably measurable spin Hall effect and / or inverse spin Hall effect in its normal state. Its current-to-spin current conversion capability can be clearly verified through spin Hall magnetoresistance and current-driven second harmonic generation tests. This material allows superconductivity and spin current generation to coexist naturally in a single material system, without the need for additional strong SOC metals, topological materials, or complex heterostructures. It fundamentally solves existing technical problems and fulfills a long-standing technical requirement.

[0097] Figure 9 This is a schematic diagram showing the SMR and fitting curves of Co / In2Bi(t) / Al2O3 devices of different thicknesses prepared in one embodiment of the present invention at different temperatures, where t represents the thickness of / In2Bi. Figure 9 As shown, based on SMR, it can be fitted that the Co / In2Bi(t) / Al2O3 device has a large spin Hall angle (SHA) and spin diffusion length (SDL) at different temperatures. Since the test mechanism is based on the synergy of the spin Hall effect and the inverse spin Hall effect, it can be proved that In2Bi has the ability to convert current to spin current.

[0098] Figure 10 This document presents the test results and fitting data for the second harmonic angle dependence of a Co / In2Bi / Al2O3 device at room temperature in one embodiment of the present invention. The horizontal axis represents the second harmonic angle α, and the vertical axis represents the in-plane rotation angle. The second harmonic rotation angle test is an alternative to the SMR test and is one of the mainstream methods for verifying current-to-spin-current conversion capabilities. Figure 10 The fitting results show that In2Bi has anti-damping like and field like contributions, and also has some thermal signal, proving that it has current-spin-current conversion capability.

[0099] Figure 11This presents the anomalous Hall resistance test results of a FeGaTe / In₂Bi / Al₂O₃ device near the Tc temperature in one embodiment of the present invention. The results show that at 6.0 K and 8.0 K, the device itself is in a non-superconducting state, thus exhibiting a standard anomalous Hall resistance test curve, which flips when the external magnetic field exceeds the coercive field, indicating a dual-resistance state. However, at 1.8 K and 2.2 K, when the external magnetic field is less than the critical field, In₂Bi transitions to a superconducting state, causing the Hall resistance Rxy of the entire device to become 0. This proves that the device is a tri-resistance state device.

[0100] Figure 12 The anomalous Hall effect test results for the FeGaTe / In2Bi / Al2O3 device at Tc temperature (1.8K) clearly show three stable plateaus, and the zero-resistance plateau is indeed zero-resistance, further proving that the device is a three-resistance device. Above Tc temperature, the non-magnetic In2Bi film in the FeGaTe / In2Bi / Al2O3 heterojunction enables the heterojunction to convert current into spin current, which can be verified by spin Hall magnetoresistance measurement (SMR) or second harmonic distortion (HDC) testing. Below Tc temperature, In2Bi becomes superconducting, transforming the entire device into a superconducting device.

[0101] Figure 13 The diagram shows the Hall resistance of the FeGaTe / In2Bi / Al2O3 device at Tc temperature (1.8K) versus the external magnetic field, illustrating the device's states under different external magnetic fields: the anomalous Hall flip at ±8000 Oe corresponds to information writing; ±5000 Oe represents information reading; and 0 Oe represents information encryption protection. This demonstrates that the FeGaTe / In2Bi / Al2O3 device can be used for information storage and encryption.

[0102] The function, state, and corresponding magnetic field of a three-resistivity device can be represented by the following table:

[0103]

[0104] Among them, H c1 and H c2 These represent the lower critical field and upper critical field in the In2Bi superconducting state, respectively.

[0105] Traditional dual-resistance devices only have high-resistance / low-resistance states. This invention forms three-resistance states: high-resistance, low-resistance, and zero-resistance through a switching mechanism. By combining the superconducting state (zero resistance) with the current-spin state (low resistance) and the high-resistance state, multi-state information storage and encryption can be achieved, improving device security and functional richness. By upgrading the traditional dual-resistance device (high-resistance / low-resistance) based solely on current-spin current conversion to a three-resistance device (high-resistance, low-resistance, zero resistance), device data encryption and multi-state information storage functions based on superconducting and spin-spin conversion states can be realized. Switching between the superconducting state and the current-spin current conversion state can be achieved through various means such as current, external magnetic field, and temperature.

[0106] Figure 14 This is a test image of the spin-orbit torque (SOT) reversal of a FeGaTe / In2Bi device at room temperature (300K). It can be seen that applying alternating current under the influence of an in-plane magnetic field can effectively achieve Hall resistance reversal, which is an alternative information writing method different from pure magnetic field reversal.

[0107] In existing publicly available technologies, no material can simultaneously possess a considerable critical temperature and maintain stable current-spin-current conversion capability over a wide temperature range under conventional thin-film fabrication conditions. In particular, material systems capable of obtaining a definite spin Hall angle through spin dynamics methods such as spin Hall magnetoresistance and second harmonic generation, and maintaining efficient spin transport within the 5.8 K–300 K range, are almost nonexistent. The realization of such materials would bring significant breakthroughs to areas such as integrated superconducting spin devices, low-energy interconnects, and switchable quantum functional devices. The results above show that the superconducting-spin-switchable device proposed in this invention, based on In–Bi-based alloy thin-film materials, can simultaneously exhibit considerable superconductivity and stable current-spin-current conversion capability (spin Hall angle 0.05–0.11, applicable temperature range 5–300 K). In the normal temperature range (5–300 K), the spin Hall angle SHA≈0.05–0.11 can be measured through spin Hall magnetoresistance (SMR) and current-driven second harmonic generation. The material's electronic structure possesses moderate conductivity and a large Berry curvature, enabling efficient charge-spin conversion. Based on the dual functions of "superconductivity" and "current-spin current conversion capability," multifunctional device structures can be constructed, integrating superconductivity and current-spin current conversion functions in the same device. This allows for the synergistic operation of dual functions such as superconducting transport, spin injection, and spin detection.

[0108] In summary, the superconducting-spin-switching device of the present invention has the following advantages:

[0109] (1) High integration of materials and functions: In the prior art, spintronic devices usually rely on strongly spin-orbit coupled metals (such as Pt, W, etc.) to generate spin current, while superconducting devices use low-temperature superconducting thin films. The two are usually located in different material layers, requiring complex heterostructure coupling, which has problems such as interface scattering, complicated preparation, and high energy consumption. This invention realizes that a single material has both superconductivity and current-spin current conversion function through In-Bi based alloy material, and completes the dual-function integration in the same thin film, which can significantly reduce structural complexity, simplify the device preparation process, and improve interface stability and repeatability.

[0110] (2) Easy to perform multi-state control: Existing superconducting or spin devices have fixed functions and can usually only operate in a single resistance state or a dual resistance state (high resistance / low resistance), lacking the ability to switch functions and control states. However, the device of the present invention can switch between the superconducting state and the current-spin current conversion state through various means such as current, external magnetic field, and temperature, thereby forming a three-resistance state device (high resistance, low resistance, zero resistance), realizing multi-state information storage and data encryption based on dual-function states, and expanding the flexibility and security of device applications.

[0111] (3) Stable performance and wide applicable temperature range: Existing spin functional materials are often affected by resistance changes or interface scattering at low temperatures, resulting in a decrease in spin current transport efficiency, and the superconducting function also needs to be optimized independently. The material of this invention maintains stable current-spin current conversion performance in the temperature range of 5.8–300 K, while exhibiting superconducting characteristics at low temperatures, achieving a synergy between wide temperature range applicability and high-efficiency function, providing a reliable material basis for spintronics, superconducting-spin magnetoresistive devices, logic gate devices, quantum devices and other superconducting-spin integrated devices.

[0112] (4) Strong functional scalability and great application potential: The materials and devices have both superconducting and spin switching functions, which can be directly used in cutting-edge application scenarios such as low-energy quantum interconnects and switchable superconducting-spin logic, which is significantly better than the applicability and scalability of traditional single-function devices.

[0113] In the device structure of this invention, when the magnetic layer is an antiferromagnetic layer, this invention can also achieve the switching between the superconducting state and the current-spin-current conversion state, and can also expand the application of the device.

[0114] The present invention provides novel functional materials and devices that can exhibit superconducting properties and efficient current-spin-current conversion capabilities in the same material system. This breaks through the limitation of the separation of traditional superconducting materials and spin materials, and realizes the integration, low energy consumption and synergistic operation of the two, laying the material foundation for the development of superconducting spintronics and related quantum devices.

[0115] 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.

[0116] 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.

[0117] 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 superconducting-spin-switching device, characterized in that, The device includes: A magnetic layer having perpendicular magnetic anisotropy; and A non-magnetic layer, wherein the non-magnetic layer is an In–Bi based alloy layer; The magnetic layer and the non-magnetic layer form a magnetic / non-magnetic heterojunction; the In-Bi based alloy layer exhibits superconducting properties below the first temperature, and can achieve current-spin-current conversion above the first temperature. The superconducting-spin-switchable device achieves switching between the superconducting state and the current-spin-current conversion state based on the magnetic / non-magnetic heterojunction, forming a three-resistance state device based on the switching, which can be used for multi-state information storage and encryption.

2. The device according to claim 1, characterized in that, The atomic ratio of In to Bi in the In–Bi-based alloy layer ranges from 1:1 to 2:1; The thickness of the In–Bi-based alloy layer is 1-100 nm.

3. The device according to claim 1, characterized in that, The device also includes: A substrate on which the magnetic / non-magnetic heterojunction is formed; and A protective layer is formed on the side of the magnetic / non-magnetic heterojunction away from the substrate.

4. The device according to claim 1, characterized in that, The magnetic layer is a ferromagnetic layer, which can be a two-dimensional magnetic material layer, a magnetic alloy layer, a multilayer metal thin film with overall magnetic properties, or a tunnel heterostructure.

5. The device according to claim 1, characterized in that, The superconducting-spin-switching device is a Holba-based device.

6. The device according to claim 1, characterized in that, The superconducting-spin-switching device is a spin valve-based device; The device further includes another magnetic layer formed on the side of the non-magnetic layer opposite to the magnetic layer.

7. The device according to claim 1, characterized in that, The superconducting-spin-switching device is a Josephson junction-based device; The device further includes a superconducting layer formed on the side of the magnetic layer opposite to the non-magnetic layer.

8. The device according to any one of claims 1-7, characterized in that, The material of the In–Bi based alloy layer is selected from InBi, In5Bi3, In2Bi, InBiSn and InBiTe.

9. The device according to any one of claims 1-7, characterized in that, The superconducting-spin-switchable device has a multi-channel structure and is used to measure Hall voltage, resistance, spin Hall magnetoresistance, and harmonic voltage respectively.

10. The device according to any one of claims 1-7, characterized in that, The superconducting-spin-switchable device is a superconducting-spin magnetoresistive device, a logic gate device, or a quantum device.

11. A superconducting-spin-switching method, characterized in that, This method is based on the superconducting spin-switched device as described in any one of claims 1-10.

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