A two-dimensional full-van der waals magnetic tunnel junction based on multi-layer barrier layer and a preparation method thereof

Abstract

The application belongs to the technical field of nanometer magnetic devices, and relates to a two-dimensional full-van der Waals magnetic tunnel junction based on a multilayer barrier layer and a preparation method thereof, which comprises an insulating substrate, an electrode A, an electrode G, a two-dimensional van der Waals magnetic layer B, a two-dimensional van der Waals barrier layer and a two-dimensional van der Waals magnetic layer F. The two-dimensional van der Waals barrier layer is two or three layers, is selected from WS2, WSe2, CuIn2PS6, In2Se3 and black phosphorus, and adjacent two barrier layers are different materials. The ferromagnetic material provided by the application has a polarizability of 70% or above, forms a magnetic tunnel junction with the two-dimensional van der Waals barrier layer material, and has a tunneling magnetoresistance ratio of 28900% or above. The application can stably work at room temperature and realize zero-current ultra-low power consumption operation.

Description

Technical Field

[0001] This invention belongs to the field of nanomagnetic device technology, and more specifically, relates to a two-dimensional full van der Waals magnetic tunneling junction based on a multilayer barrier layer and its preparation method. Background Technology

[0002] As one of the core devices in spintronics, the magnetic tunneling junction (MTJ) relies on the parallel or antiparallel arrangement of the spin magnetic moments of the ferromagnetic electrodes on both sides to form two conduction states: low resistance and high resistance. Due to its large tunneling magnetoresistance ratio and non-volatile storage characteristics, it is widely used in spintronic devices such as high-precision magnetic field sensing, high-speed magnetic random access memory (MRAM), and low-power in-memory computing chips. A conventional MMT structure consists of two layers of ferromagnetic electrodes sandwiched in an insulating tunneling barrier layer. Under the control of an external magnetic field, the orientation of the magnetic moments of the two magnetic layers reverses from parallel to antiparallel, significantly changing the magnitude of the tunneling current, thereby achieving electrically and magnetically controlled switching between high and low resistance states.

[0003] Traditional magnetic tunneling junctions typically use bulk ferromagnetic metals such as Fe, Co, CoFeB, and NiFe as ferromagnetic electrodes, combined with oxides such as MCo as tunneling barrier layers to fabricate heterostructures. However, severe lattice mismatch exists between traditional bulk materials and oxide barriers, leading to defects such as dangling bonds, dislocations, and interface impurities at the heterostructure interface. These defects can cause problems such as increased spin scattering, decreased tunneling magnetoresistance, and reduced device on / off ratio, significantly limiting device stability and spin transport efficiency. Two-dimensional van der Waals materials possess atomically flat surfaces without dangling bonds, and the interlayer is bound by van der Waals forces. When fabricating heterostructures, they are not constrained by lattice matching conditions, enabling the construction of atomically clean and defect-free perfect interfaces, thus mitigating interface spin loss at its source. However, existing single-component two-dimensional intrinsic ferromagnetic materials generally have Curie temperatures below room temperature, failing to meet the operating requirements of room-temperature devices. Furthermore, traditional composite magnetic tunneling junctions often mix bulk metals and two-dimensional materials, failing to fully utilize the intrinsic advantages of van der Waals interfaces. Therefore, constructing a fully van der Waals magnetic tunneling junction in which all functional layers (ferromagnetic electrodes and insulating barrier layers) are stacked from two-dimensional van der Waals materials to achieve efficient spin tunneling transport at room temperature has become a difficult problem and a research hotspot that urgently needs to be solved in the field of spintronic devices.

[0004] To address the aforementioned issues, it is urgent to increase the room-temperature magnetic reluctance of the magnetic tunneling junction, thereby improving the stability of the magnetic tunneling junction during room-temperature operation. Summary of the Invention

[0005] In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer and its preparation method. The purpose is to improve the room temperature magnetic reluctance of the magnetic tunneling junction, thereby improving the room temperature operation stability of the magnetic tunneling junction.

[0006] According to a first aspect of the present invention, a two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers is provided, the magnetic tunneling junction comprising an insulating substrate, an electrode A, an electrode G, a two-dimensional van der Waals magnetic layer B, a two-dimensional van der Waals barrier layer C, a two-dimensional van der Waals barrier layer D, and a two-dimensional van der Waals magnetic layer F. The two-dimensional van der Waals magnetic layer B and the two-dimensional van der Waals magnetic layer F are each independently selected from Fe. 3-a Ga b Te 2-c Fe 3-a GabGedTe 2-c Co-Fe 3-a Ga b Te 2-c Co-Fe 3-a Ge d Te 2-c Where a = -3.0~3.0, b = 0.01~5.0, c = -1~1, d = 0.01~5.0; The structure of the magnetic tunnel junction is as follows: from bottom to top, an insulating substrate, an electrode A, a two-dimensional van der Waals magnetic layer B, a two-dimensional van der Waals barrier layer C, a two-dimensional van der Waals barrier layer D, a two-dimensional van der Waals magnetic layer F, and an electrode G are stacked sequentially. Alternatively, the structure of the magnetic tunnel junction is as follows: Electrode A and Electrode G are located at opposite ends of the insulating surface of the insulating substrate and do not contact each other; the two-dimensional van der Waals magnetic layer B is in contact with Electrode A, and the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate and does not contact Electrode G; a portion of the two-dimensional van der Waals barrier layer C is located above the two-dimensional van der Waals magnetic layer B, and the portion of the two-dimensional van der Waals barrier layer C other than the portion above the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate and does not contact Electrode G; the two-dimensional van der Waals barrier layer D is located on the surface of the two-dimensional van der Waals barrier layer C and does not contact Electrode G; the two-dimensional van der Waals magnetic layer F is located above the two-dimensional van der Waals barrier layer D, and one end is in contact with Electrode G.

[0007] According to another aspect of the present invention, a two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers is provided, the magnetic tunneling junction comprising an insulating substrate, an electrode A, an electrode G, a two-dimensional van der Waals magnetic layer B, a two-dimensional van der Waals barrier layer C, a two-dimensional van der Waals barrier layer D, a two-dimensional van der Waals barrier layer E, and a two-dimensional van der Waals magnetic layer F. The two-dimensional van der Waals magnetic layer B and the two-dimensional van der Waals magnetic layer F are each independently selected from Fe. 3-a Ga b Te 2-c Fe 3-a GabGedTe 2-c Co-Fe 3-a Gab Te 2-c Co-Fe 3-a Ge d Te 2-c Where a = -3.0~3.0, b = 0.01~5.0, c = -1~1, d = 0.01~5.0; The structure of the magnetic tunnel junction is as follows: from bottom to top, an insulating substrate, electrode A, two-dimensional van der Waals magnetic layer B, two-dimensional van der Waals barrier layer C, two-dimensional van der Waals barrier layer D, two-dimensional van der Waals barrier layer E, two-dimensional van der Waals magnetic layer F and electrode G are stacked sequentially. Alternatively, the structure of the magnetic tunnel junction may be as follows: Electrode A and Electrode G are located at opposite ends of the insulating surface of the insulating substrate and do not contact each other; the two-dimensional van der Waals magnetic layer B is in contact with Electrode A, and is located on the surface of the insulating substrate, but does not contact Electrode G; a portion of the two-dimensional van der Waals barrier layer C is located above the two-dimensional van der Waals magnetic layer B, and the portion of the two-dimensional van der Waals barrier layer C other than the portion above the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate, but does not contact Electrode G; the two-dimensional van der Waals barrier layer D is located on the surface of the two-dimensional van der Waals barrier layer C and does not contact Electrode G; the two-dimensional van der Waals barrier layer E is located on the surface of the two-dimensional van der Waals barrier layer D and does not contact Electrode G; the two-dimensional van der Waals magnetic layer F is located above the two-dimensional van der Waals barrier layer E, and one end is in contact with Electrode G.

[0008] Preferably, the materials of the two-dimensional van der Waals barrier layer C and the two-dimensional van der Waals barrier layer D are each independently selected from WS2, WSe2, CuIn2PS6, In2Se3 and black phosphorus.

[0009] Preferably, the materials of the two-dimensional van der Waals barrier layer C, the two-dimensional van der Waals barrier layer D, and the two-dimensional van der Waals barrier layer E are each independently selected from WS2, WSe2, CuIn2PS6, In2Se3, and black phosphorus, and adjacent barrier layers of the three barrier layers C, D, and E are made of different materials.

[0010] According to another aspect of the present invention, a two-dimensional full van der Waals magnetic tunnel array based on a multi-layer barrier layer is provided, comprising a plurality of mutually independent two-dimensional full van der Waals magnetic tunnel arrays based on a multi-layer barrier layer.

[0011] According to another aspect of the present invention, a method for preparing the aforementioned two-dimensional full van der Waals magnetic tunnel junction based on a multi-layer barrier layer is provided, comprising the following steps: (1) Electrode A is deposited on an insulating substrate by vapor deposition; (2) Mechanically peel off or deposit two-dimensional van der Waals magnetic layer B, two-dimensional van der Waals barrier layer C, two-dimensional van der Waals barrier layer D and two-dimensional van der Waals magnetic layer F sequentially on electrode A; (3) Electrode G is deposited on the two-dimensional van der Waals magnetic layer F; Or it may include the following steps: S1: Spin-coating photoresist onto an insulating substrate; S2: Electrode patterns are drawn using photolithography. S3: Electrode A and electrode G are deposited on the electrode pattern obtained in step S2. Electrode A and electrode G are located at both ends of the insulating surface of the insulating substrate and do not contact each other. S4: Sequentially mechanically peel off or deposit a two-dimensional van der Waals magnetic layer B, a two-dimensional van der Waals barrier layer C, a two-dimensional van der Waals barrier layer D, and a two-dimensional van der Waals magnetic layer F on an insulating substrate; the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate, and it is in contact with electrode A but not with electrode G; a portion of the two-dimensional van der Waals barrier layer C is located on top of the two-dimensional van der Waals magnetic layer B, and the portion of the two-dimensional van der Waals barrier layer C other than the top portion of the two-dimensional van der Waals magnetic layer B is located on the insulating substrate, and it is not in contact with electrode G; the two-dimensional van der Waals barrier layer D is located on the surface of the two-dimensional van der Waals barrier layer C, and it is not in contact with electrode G; the two-dimensional van der Waals magnetic layer F is located on top of the two-dimensional van der Waals barrier layer D, and one end is in contact with electrode G, thus obtaining a two-dimensional full van der Waals magnetic tunnel junction.

[0012] According to another aspect of the present invention, a method for preparing the aforementioned two-dimensional full van der Waals magnetic tunnel junction based on a multi-layer barrier layer is provided, comprising the following steps: (1) Electrode A is deposited on an insulating substrate by vapor deposition; (2) Mechanically peel off or deposit two-dimensional van der Waals magnetic layer B, two-dimensional van der Waals barrier layer C, two-dimensional van der Waals barrier layer D, two-dimensional van der Waals barrier layer E and two-dimensional van der Waals magnetic layer F sequentially on electrode A; (3) Electrode G is deposited on the two-dimensional van der Waals magnetic layer F; Or it may include the following steps: S1: Spin-coating photoresist onto an insulating substrate; S2: Electrode patterns are drawn using photolithography. S3: Electrode A and electrode G are deposited on the electrode pattern obtained in step S2. Electrode A and electrode G are located at both ends of the insulating surface of the insulating substrate and do not contact each other. S4: Sequentially mechanically peel off or deposit a two-dimensional van der Waals magnetic layer B, a two-dimensional van der Waals barrier layer C, a two-dimensional van der Waals barrier layer D, a two-dimensional van der Waals barrier layer E, and a two-dimensional van der Waals magnetic layer F on an insulating substrate; the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate, and it is in contact with electrode A but not with electrode G; a portion of the two-dimensional van der Waals barrier layer C is located on top of the two-dimensional van der Waals magnetic layer B, and the portion of the two-dimensional van der Waals barrier layer C other than the top portion of the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate, and it is not in contact with electrode G; the two-dimensional van der Waals barrier layer D is located on the surface of the two-dimensional van der Waals barrier layer C, and it is not in contact with electrode G; the two-dimensional van der Waals barrier layer E is located on top of the two-dimensional van der Waals barrier layer E, and one end is in contact with electrode G, thus obtaining a two-dimensional full van der Waals magnetic tunnel junction.

[0013] Preferably, the deposition method is chemical vapor deposition, molecular beam epitaxy, or magnetron sputtering.

[0014] Preferably, the insulating substrate is SiO2, Al2O3, GaAs, polyimide, or fluorinated mica.

[0015] Preferably, electrode A and electrode G are each independently selected from metal electrodes Au, Cr, Pt, Al, Cu or Ti.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: (1) The present invention is based on a two-dimensional full van der Waals magnetic tunneling junction with multiple barrier layers, and uses a Ga-based two-dimensional van der Waals ferromagnetic material Fe with room temperature ferromagnetism. 3-a GabTe2-c, Fe 3-a Ga b Ge d Te 2-c Co-Fe 3-a Ga b Te 2-c Or Co-Fe 3-a Ge d Te 2-c(a=-3.0~3.0, b=0.01~5.0, c=-1~1, d=0.01~5.0), as the two-dimensional van der Waals magnetic layer, two-dimensional van der Waals semiconductor materials WS2, WSe2, CuIn2PS6, In2Se3, and black phosphorus are used as barrier layers. Due to the energy level differences formed by different barrier layers, zero bias magnetoresistance is achieved. The tunneling magnetoresistance ratio of the magnetic tunneling junction reaches over 400% at room temperature, enabling reliable operation with ultra-low power consumption and zero current. This solves the technical problem that magnetic tunneling junctions based on other two-dimensional van der Waals ferromagnets cannot operate stably at room temperature.

[0017] (2) The two-dimensional full van der Waals magnetic tunnel junction prepared by the present invention avoids the lattice mismatch problem caused by traditional materials; the ferromagnetic material used achieves an ideal magnetoresistance ratio at room temperature and can work stably with ultra-low power consumption.

[0018] (3) The two-dimensional full van der Waals magnetic tunneling junction prepared by the present invention has a better energy level matching degree of the three barrier layers and a higher magnetic resistance.

[0019] (4) The two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer prepared in this invention preferably uses a four-terminal metal electrode, which can avoid the influence of contact resistance and make the test results more reliable.

[0020] (5) The thickness of the two-dimensional full van der Waals magnetic tunneling junction based on a multilayer barrier layer prepared by the present invention can be arbitrarily adjusted from 20 to 500 nm, and it is compatible with flexible substrates and is suitable for wearable magnetoelectronic devices and other fields.

[0021] (6) The two-dimensional full van der Waals magnetic tunneling junction based on a multilayer barrier layer prepared by the present invention can be prepared by chemical vapor deposition, molecular beam epitaxy or magnetron sputtering, etc., and realizes the possibility of compatibility with logic circuits and other fields. Attached Figure Description

[0022] Figure 1 This invention provides a schematic diagram of a two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer.

[0023] Figure 2 This is a schematic diagram of another two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer provided by the present invention.

[0024] Figure 3 This is a schematic diagram of a magnetic tunneling junction consisting of three sequentially stacked barrier layers, as provided by the present invention.

[0025] Figure 4 This is a flowchart illustrating a two-dimensional full van der Waals magnetic tunneling structure based on a multi-layer barrier layer, as provided in an embodiment of the present invention.

[0026] Figure 5This is a process flow diagram of a two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer, provided for an embodiment of the present invention.

[0027] Figure 6 The figure shows the test results of a two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer, as provided in an embodiment of the present invention.

[0028] In all the figures, the same reference numerals are used to denote the same elements or structures, wherein: 1-insulating substrate, 2-electrode A, 3-two-dimensional van der Waals magnetic layer B, 4-two-dimensional van der Waals barrier layer C, 5-two-dimensional van der Waals barrier layer D, 6-two-dimensional van der Waals barrier layer E, 7-two-dimensional van der Waals magnetic layer F, 8-electrode G. Detailed Implementation

[0029] 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 accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0030] The following is an example of a magnetic tunneling junction with two barrier layers.

[0031] Example 1 (1) Spin-coat the first layer of photoresist ARP5350 on the SiO2 substrate at a speed of 6000 r / min for 60 s, and bake it on a hot plate at a temperature of 100 ℃ for 6 min; (2) Electrode patterns for magnetic tunnel junction devices were fabricated using laser direct writing technology with an exposure dose of 130 mW. The samples were then baked on a heating plate for 1 min to obtain sample A. (3) Sample A was developed in a tetramethylammonium hydroxide aqueous solution, and then Au / Cr electrode was deposited using an electron beam evaporation system to a thickness of 10 nm to obtain sample B; (4) Soak sample B in acetone solution for 10 min to remove photoresist ARP5350, then rinse it with deionized water and dry it with nitrogen gun to obtain sample C. (5) The magnetic layer material Fe3GaTe2 with a thickness of 10 nm was obtained by mechanical peeling. Fe3GaTe2 was transferred to sample C using PDMS glue as the first magnetic layer, so that one end of Fe3GaTe2 was in contact with the left electrode, and the other end that was not in contact with the left electrode was in contact with the insulating substrate, but not with the right electrode, thus obtaining sample D. (6) Semiconductor material WSe2 with a thickness of 1 nm was obtained by mechanical peeling. WSe2 was transferred to sample D using PDMS adhesive, so that one end of WSe2 was in contact with the first layer Fe3GaTe2, and the other end that was not in contact with the first layer Fe3GaTe2 was in contact with the insulating substrate, but not with the right electrode, thus obtaining sample E. (7) Semiconductor material In2Se3 with a thickness of 1 nm was obtained by mechanical exfoliation. In2Se3 was transferred to sample E using PDMS adhesive, so that the second layer of In2Se3 was located on the first layer of WSe2, but did not contact the right electrode, thus obtaining sample F; (8) The magnetic layer material Fe3GaTe2 with a thickness of 10 nm was obtained by mechanical exfoliation. Fe3GaTe2 was transferred to sample F using PDMS glue as the second magnetic layer. One end of Fe3GaTe2 was in contact with the right electrode, and the other end, which was not in contact with the right electrode, was in contact with the second layer WSe2, but not with the left electrode, thus obtaining sample G. The two magnetic layers were separated by two barrier layers, thus obtaining a two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers.

[0032] Figure 1 This is a schematic diagram of a two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer in this embodiment. Electrodes A2 and G8 are located at opposite ends of the insulating surface of the insulating substrate 1 and do not contact each other. The two-dimensional van der Waals magnetic layer B3 is in contact with electrode A2, and is located on the insulating surface of the insulating substrate 1, but does not contact electrode G8. A portion of the two-dimensional van der Waals barrier layer C4 is located above the two-dimensional van der Waals magnetic layer B3. The portion of the two-dimensional van der Waals barrier layer C4 other than the portion above the two-dimensional van der Waals magnetic layer B3 is located on the insulating surface of the insulating substrate 1, and does not contact electrode G8. The two-dimensional van der Waals barrier layer D5 is located on the surface of the two-dimensional van der Waals barrier layer C4, and does not contact electrode G8. The two-dimensional van der Waals magnetic layer F7 is located above the two-dimensional van der Waals barrier layer D5, and one end is in contact with electrode G8. The two-dimensional van der Waals magnetic layers B3 and F7... 7 is separated by a two-dimensional van der Waals barrier layer C4 and a two-dimensional van der Waals barrier layer D5; the right half of the structure and the left half together form an array.

[0033] Example 2 Replace the semiconductor material In2Se3 in step (7) of Example 1 with black phosphorus, and the remaining steps are the same as in Example 1.

[0034] Example 3 Replace the semiconductor material In2Se3 in step (7) of Example 1 with CuIn2PS6, and the remaining steps are the same as in Example 1.

[0035] Example 4 Replace the Fe3GaTe2 magnetic layer material in step (5) of Example 1 with Co-Fe3GaGeTe2, replace the In2Se3 semiconductor material in step (7) with black phosphorus, and the remaining steps are the same as in Example 1.

[0036] Example 5 Replace the magnetic layer material Fe3GaTe2 in step (5) of Example 1 with Fe3GaGeTe2, replace the semiconductor material In2Se3 in step (7) with CuIn2PS6, and the remaining steps are the same as in Example 1.

[0037] Example 6 Replace the Fe3GaTe2 magnetic layer material in step (5) of Example 1 with Co-Fe3GeTe2, replace the In2Se3 semiconductor material in step (7) with In2Se3, and the remaining steps are the same as in Example 1.

[0038] The following is an example of a magnetic tunneling junction with a three-layer barrier layer.

[0039] Example 7 (1) Spin-coat the first layer of photoresist ARP5350 on the SiO2 substrate at a speed of 6000 r / min for 60 s, and bake it on a hot plate at a temperature of 100 ℃ for 6 min; (2) Electrode patterns for magnetic tunnel junction devices were fabricated using laser direct writing technology with an exposure dose of 130 mW. The samples were then baked on a heating plate for 1 min to obtain sample A. (3) Sample A was developed in a tetramethylammonium hydroxide aqueous solution, and then Au / Cr electrode was deposited using an electron beam evaporation system to a thickness of 10 nm to obtain sample B; (4) Soak sample B in acetone solution for 10 min to remove photoresist ARP5350, then rinse it with deionized water and dry it with nitrogen gun to obtain sample C. (5) The magnetic layer material Fe3GaTe2 with a thickness of 10 nm was obtained by mechanical peeling. Fe3GaTe2 was transferred to sample C using PDMS glue as the first magnetic layer, so that one end of Fe3GaTe2 was in contact with the left electrode, and the other end that was not in contact with the left electrode was in contact with the insulating substrate, but not with the right electrode, thus obtaining sample D. (6) Semiconductor material WSe2 was obtained by mechanical peeling and used as the first barrier layer with a thickness of 1 nm. PDMS adhesive was used to transfer WS2 onto sample D, so that one end of WSe2 was in contact with the first layer Fe3GaTe2, and the other end that was not in contact with the first layer Fe3GaTe2 was in contact with the insulating substrate, but not with the right electrode, thus obtaining sample E. (7) Semiconductor material WS2 with a thickness of 1 nm was obtained by mechanical peeling. WS2 was transferred to sample E using PDMS adhesive, so that the second barrier layer WS2 was located on the first barrier layer WSe2, but did not contact the right electrode, thus obtaining sample F; (8) Semiconductor material WSe2 with a thickness of 1 nm was obtained by mechanical peeling. WSe2 was transferred to sample F using PDMS adhesive, so that the third barrier layer WSe2 was located on the second barrier layer WS2, but did not contact the right electrode, thus obtaining sample G. (9) The magnetic layer material Fe3GaTe2 was obtained by mechanical exfoliation and used as the second magnetic layer with a thickness of 10 nm. Fe3GaTe2 was transferred to sample G using PDMS glue as the second magnetic layer, so that one end of Fe3GaTe2 was in contact with the right electrode, and the other end, which was not in contact with the right electrode, was in contact with the second layer WSe2, but not with the left electrode, thus obtaining sample H. The two magnetic layers were separated by three barrier layers, thus obtaining a two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers.

[0040] Figure 4 This is a flowchart illustrating the fabrication process of a two-dimensional full van der Waals magnetic tunnel junction based on multiple barrier layers in this embodiment, primarily reflecting the device structure formation process. The serial numbers represent the corresponding processes: ① Evaporation of metal electrodes; ② Fabrication of the first two-dimensional van der Waals magnetic layer material; ③ Fabrication of the first two-dimensional van der Waals barrier layer material; ④ Fabrication of the second two-dimensional van der Waals barrier layer material; ⑤ Fabrication of the third two-dimensional van der Waals barrier layer material; ⑥ Fabrication of the second two-dimensional van der Waals magnetic layer material.

[0041] Figure 5 This is a flowchart illustrating the fabrication process of a two-dimensional full van der Waals magnetic tunnel junction based on multiple barrier layers in this embodiment. Figure 4The device structure fabrication process is as follows: First, electrode patterns for the tunneling junction are drawn on an insulating substrate using photolithography. Then, metal electrodes with a thickness of 1-110 nm are fabricated on the electrode patterns using electron beam evaporation. After removing the photoresist, a Ga-based room-temperature ferromagnetic crystal is mechanically exfoliated or deposited on the metal electrodes as the first two-dimensional van der Waals magnetic layer with a thickness of 1-110 nm. Subsequently, a semiconductor material is mechanically exfoliated or deposited on the first two-dimensional van der Waals magnetic layer as a barrier layer with a thickness of 1-20 nm. Then, a second semiconductor material is mechanically exfoliated or deposited on the first two-dimensional van der Waals barrier layer with a thickness of 1-20 nm. Subsequently, a third semiconductor material is mechanically exfoliated or deposited on the second two-dimensional van der Waals barrier layer with a thickness of 1-20 nm. Finally, a Ga-based room-temperature ferromagnetic crystal is mechanically exfoliated or deposited on the third two-dimensional van der Waals barrier layer as the second magnetic layer with a thickness of 1-100 nm, resulting in a two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers. Repeated operations on the same insulating substrate yielded the same structure, forming a two-dimensional full van der Waals magnetic tunneling array based on multiple barrier layers.

[0042] Figure 2 This is a schematic diagram of a two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer in this embodiment. Electrodes A2 and G8 are located at opposite ends of the insulating surface of the insulating substrate 1 and do not contact each other. The two-dimensional van der Waals magnetic layer B3 is in contact with electrode A2, and is located on the insulating surface of the insulating substrate 1, but does not contact electrode G8. A portion of the two-dimensional van der Waals barrier layer C4 is located above the two-dimensional van der Waals magnetic layer B3. The portion of the two-dimensional van der Waals barrier layer C4 other than the portion above the two-dimensional van der Waals magnetic layer B3 is located on the insulating surface of the insulating substrate 1, and does not contact electrode G8. The two-dimensional van der Waals barrier layer D5 is located on the surface of the two-dimensional van der Waals barrier layer C4, and does not contact electrode G8. The two-dimensional van der Waals barrier layer E6 is located on the surface of the two-dimensional van der Waals barrier layer D5, and does not contact electrode G8. The two-dimensional van der Waals magnetic layer F... 7 is located above the two-dimensional van der Waals barrier layer E6, and one end is in contact with the electrode G8; the two-dimensional van der Waals magnetic layer B3 and the two-dimensional van der Waals magnetic layer F7 are separated by two-dimensional van der Waals barrier layer C4, two-dimensional van der Waals barrier layer D5, and two-dimensional van der Waals barrier layer E6; the right half of the structure and the left half together form an array.

[0043] Example 8 Replace the third barrier layer WSe2 in step (8) of Example 7 with CuIn2PS6, and the remaining steps are the same as in Example 7.

[0044] Example 9 Replace the third barrier layer WSe2 in step (8) of Example 7 with In2Se3, and the remaining steps are the same as in Example 7.

[0045] Example 10 Replace the third barrier layer WSe2 in step (8) of Example 7 with black phosphorus, and the remaining steps are the same as in Example 7.

[0046] Example 11 Replace the first barrier layer WSe2 in step (6) of Example 7 with In2Se3, and the remaining steps are the same as in Example 7.

[0047] Example 12 Replace the second magnetic layer Fe3GaTe2 in step (9) of Example 7 with Fe3GaGeTe2, and the remaining steps are the same as in Example 7.

[0048] Example 13 Replace the first magnetic layer Fe3GaTe2 in step (5) of Example 7 with Fe3GaGeTe2, and the remaining steps are the same as in Example 7.

[0049] Example 14 Replace the materials of the first magnetic layer Fe3GaTe2 and the second magnetic layer Fe3GaTe2 in steps (5) and (9) of Example 7 with Fe3GaGeTe2 and Co-Fe3GeTe2, respectively, and the remaining steps are the same as in Example 7.

[0050] Example 15 In Example 7, the first magnetic layer Fe3GaTe2 and the second magnetic layer Fe3GaTe2 in steps (5) and (9) are replaced with materials Co-Fe3GaTe2 and Co-Fe3GeTe2, respectively, and the remaining steps are the same as in Example 7.

[0051] Example 16 Replace the first magnetic layer Fe3GaTe2 in step (5) of Example 7 with Fe3GaGeTe2, replace the third barrier layer WSe2 in step (8) with black phosphorus, and the remaining steps are the same as in Example 7.

[0052] Example 17 Replace the first magnetic layer Fe3GaTe2 in step (5) of Example 7 with Co-Fe3GaGeTe2, replace the third barrier layer WSe2 in step (8) with In2Se3, and the remaining steps are the same as in Example 7.

[0053] Example 18 Replace the first magnetic layer Fe3GaTe2 in step (5) of Example 7 with Fe3GaGeTe2, and replace the third barrier layer WSe2 in step (8) with In2Se3. The remaining steps are the same as in Example 7.

[0054] The following is an example of a magnetic tunneling junction with two barrier layers.

[0055] Example 19 (1) Using a mask, an Au electrode with a thickness of 10 nm was deposited by electron beam evaporation system to obtain sample A; (2) A magnetic layer B material Fe3GaTe2 with a thickness of 10 nm was deposited on sample A by chemical vapor deposition to obtain sample B; (3) A barrier layer C material In2Se3 with a thickness of 1 nm was deposited on sample B by chemical vapor deposition to obtain sample C; (4) A barrier layer of black phosphorus material D with a thickness of 1 nm was deposited on sample C by chemical vapor deposition to obtain sample D.

[0056] (5) A magnetic layer F material Fe3GaTe2 with a thickness of 10 nm was deposited on sample D by chemical vapor deposition to obtain sample E. The two magnetic layers are separated by two barrier layers, thus obtaining a two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers.

[0057] The following is an example of a magnetic tunneling junction with a three-layer barrier layer.

[0058] Example 20 (1) Using a mask, an Au electrode with a thickness of 10 nm was deposited by electron beam evaporation system to obtain sample A; (2) A magnetic layer of material Fe3GaTe2 with a thickness of 10 nm was deposited on sample A by magnetron sputtering to obtain sample B; (3) A barrier layer C material In2Se3 with a thickness of 1 nm was deposited on sample B by magnetron sputtering to obtain sample C; (4) A barrier layer of black phosphorus material D with a thickness of 1 nm was deposited on sample C by magnetron sputtering to obtain sample D.

[0059] (6) A barrier layer E material, CuIn2PS6, with a thickness of 1 nm was deposited on sample D by magnetron sputtering to obtain sample E. (5) A magnetic layer F material Fe3GeTe2 with a thickness of 10 nm was deposited on sample E by chemical vapor deposition to obtain sample F. The two magnetic layers are separated by three barrier layers, thus obtaining a two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers.

[0060] Example 21 (1) Using a mask, an Au electrode with a thickness of 10 nm was deposited by electron beam evaporation system to obtain sample A; (2) A magnetic layer of material Fe3GeTe2 with a thickness of 10 nm was deposited on sample A by molecular beam epitaxy to obtain sample B; (3) A barrier layer C material In2Se3 with a thickness of 1 nm was deposited on sample B by molecular beam epitaxy to obtain sample C; (4) A barrier layer material WS2 with a thickness of 1 nm was deposited on sample C by molecular beam epitaxy to obtain sample D.

[0061] (6) A barrier layer E material, CuIn2PS6, with a thickness of 1 nm, was deposited on sample D by molecular beam epitaxy to obtain sample E. (5) A magnetic layer F material Fe3GaTe2 with a thickness of 10 nm was deposited on sample E by molecular beam epitaxy to obtain sample F. The two magnetic layers are separated by three barrier layers, thus obtaining a two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers.

[0062] Figure 3 This is a schematic diagram of the structure of a two-dimensional full van der Waals magnetic tunnel array based on multiple barrier layers in this embodiment. From bottom to top, they are: insulating substrate 1, electrode A 2, two-dimensional van der Waals magnetic layer B 3, two-dimensional van der Waals barrier layer C 4, two-dimensional van der Waals barrier layer D 5, two-dimensional van der Waals barrier layer E 6, two-dimensional van der Waals magnetic layer F 7, and electrode G 8.

[0063] The two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers of this invention has the following function: by controlling the external magnetic field, the electron spins of the two magnetic layers are made to be in a parallel or antiparallel state, thereby realizing the switching between low-resistance state and high-resistance state.

[0064] The magnetic tunneling junction of this invention has a ferromagnetic material polarization of 70% or higher, and the magnetic tunneling junction device can operate stably at room temperature with a tunneling magnetoresistance ratio of up to 28935%.

[0065] Table 1 below shows the magnetic reluctance of different magnetic tunnel junction structures at 2K and 300K.

[0066] Table 1. Magnetic reluctance of magnetic tunnel junctions with different structures at 2K and 300K.

[0067] Figure 6 This is a test result diagram of a two-dimensional full van der Waals magnetic tunneling device based on a multi-layer barrier layer, provided in an embodiment of the present invention. Figure 6The left side shows the magnetoresistance ratio of the Fe3GaTe2 / WSe2 / WS2 / WSe2 / Fe3GaTe2 (sample in Example 7) magnetic tunneling junction at 2K, which is 28935%. Figure 6 The right side shows the magnetoresistance ratio of the Fe3GaTe2 / WSe2 / WS2 / WSe2 / Fe3GaTe2 (sample in Example 7) magnetic tunneling junction at 300K, which is 406%.

[0068] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers, characterized in that, The magnetic tunneling junction includes an insulating substrate (1), an electrode A (2), an electrode G (8), a two-dimensional van der Waals magnetic layer B (3), a two-dimensional van der Waals barrier layer C (4), a two-dimensional van der Waals barrier layer D (5), and a two-dimensional van der Waals magnetic layer F (7). The two-dimensional van der Waals magnetic layer B(3) and the two-dimensional van der Waals magnetic layer F(7) are each independently selected from Fe 3-a Ga b Te 2-c Fe 3-a GabGedTe 2-c Co-Fe 3-a Ga b Te 2-c Co-Fe 3-a Ge d Te 2-c Where a = -3.0~3.0, b = 0.01~5.0, c = -1~1, d = 0.01~5.0; The structure of the magnetic tunnel junction is as follows: from bottom to top, an insulating substrate (1), an electrode A (2), a two-dimensional van der Waals magnetic layer B (3), a two-dimensional van der Waals barrier layer C (4), a two-dimensional van der Waals barrier layer D (5), a two-dimensional van der Waals magnetic layer F (7), and an electrode G (8) are stacked sequentially. Alternatively, the structure of the magnetic tunnel junction is as follows: the electrodes A (2) and G (8) are located at opposite ends of the insulating surface of the insulating substrate (1) and do not contact each other; the two-dimensional van der Waals magnetic layer B (3) is in contact with the electrode A (2), the two-dimensional van der Waals magnetic layer B (3) is located on the surface of the insulating substrate (1), and the two-dimensional van der Waals magnetic layer B (3) does not contact the electrode G (8); a portion of the two-dimensional van der Waals barrier layer C (4) is located above the two-dimensional van der Waals magnetic layer B (3), the two-dimensional The portion of the van der Waals barrier layer C (4) located above the two-dimensional van der Waals magnetic layer B (3) is located on the surface of the insulating substrate (1), and the two-dimensional van der Waals barrier layer C (4) does not contact the electrode G (8); the two-dimensional van der Waals barrier layer D (5) is located on the surface of the two-dimensional van der Waals barrier layer C (4), and the two-dimensional van der Waals barrier layer D (5) does not contact the electrode G (8); the two-dimensional van der Waals magnetic layer F (7) is located above the two-dimensional van der Waals barrier layer D (5), and one end is in contact with the electrode G (8).

2. A two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers, characterized in that, The magnetic tunneling junction includes an insulating substrate (1), an electrode A (2), an electrode G (8), a two-dimensional van der Waals magnetic layer B (3), a two-dimensional van der Waals barrier layer C (4), a two-dimensional van der Waals barrier layer D (5), a two-dimensional van der Waals barrier layer E (6), and a two-dimensional van der Waals magnetic layer F (7). The two-dimensional van der Waals magnetic layer B(3) and the two-dimensional van der Waals magnetic layer F(7) are each independently selected from Fe 3-a Ga b Te 2-c Fe 3-a GabGedTe 2-c Co-Fe 3-a Ga b Te 2-c Co-Fe 3-a Ge d Te 2-c Where a = -3.0~3.0, b = 0.01~5.0, c = -1~1, d = 0.01~5.0; The structure of the magnetic tunnel junction is as follows: from bottom to top, an insulating substrate (1), an electrode A (2), a two-dimensional van der Waals magnetic layer B (3), a two-dimensional van der Waals barrier layer C (4), a two-dimensional van der Waals barrier layer D (5), a two-dimensional van der Waals barrier layer E (6), a two-dimensional van der Waals magnetic layer F (7), and an electrode G (8) are stacked sequentially. Alternatively, the structure of the magnetic tunnel junction is as follows: the electrodes A (2) and G (8) are located at opposite ends of the insulating surface of the insulating substrate (1) and do not contact each other; the two-dimensional van der Waals magnetic layer B (3) is in contact with the electrode A (2), the two-dimensional van der Waals magnetic layer B (3) is located on the surface of the insulating substrate (1), and the two-dimensional van der Waals magnetic layer B (3) does not contact the electrode G (8); a portion of the two-dimensional van der Waals barrier layer C (4) is located above the two-dimensional van der Waals magnetic layer B (3), and the two-dimensional van der Waals barrier layer C (4) is located above the two-dimensional van der Waals magnetic layer B (3) The outer portion is located on the surface of the insulating substrate (1), and the two-dimensional van der Waals barrier layer C (4) does not contact the electrode G (8); the two-dimensional van der Waals barrier layer D (5) is located on the surface of the two-dimensional van der Waals barrier layer C (4), and the two-dimensional van der Waals barrier layer D (5) does not contact the electrode G (8); the two-dimensional van der Waals barrier layer E (6) is located on the surface of the two-dimensional van der Waals barrier layer D (5), and the two-dimensional van der Waals barrier layer E (6) does not contact the electrode G (8); the two-dimensional van der Waals magnetic layer F (7) is located on the upper part of the two-dimensional van der Waals barrier layer E (6), and one end is in contact with the electrode G (8).

3. The two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers as described in claim 1, characterized in that, The materials of the two-dimensional van der Waals barrier layer C (4) and the two-dimensional van der Waals barrier layer D (5) are each independently selected from WS2, WSe2, CuIn2PS6, In2Se3 and black phosphorus.

4. The two-dimensional full van der Waals magnetic tunneling junction based on multiple barrier layers as described in claim 2, characterized in that, The materials of the two-dimensional van der Waals barrier layer C (4), two-dimensional van der Waals barrier layer D (5) and two-dimensional van der Waals barrier layer E (6) are each independently selected from WS2, WSe2, CuIn2PS6, In2Se3 and black phosphorus, and the two adjacent barrier layers of the three barrier layers C (4), D (5) and E (6) are made of different materials.

5. A two-dimensional full van der Waals magnetic tunnel array based on multiple barrier layers, characterized in that, It includes multiple independent two-dimensional full van der Waals magnetic tunneling junctions based on multiple barrier layers as described in any one of claims 1-4.

6. The method for preparing a two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer as described in claim 1 or 3, characterized in that, Includes the following steps: (1) Electrode A is deposited on an insulating substrate by vapor deposition; (2) Mechanically peel off or deposit two-dimensional van der Waals magnetic layer B, two-dimensional van der Waals barrier layer C, two-dimensional van der Waals barrier layer D and two-dimensional van der Waals magnetic layer F sequentially on electrode A; (3) Electrode G is deposited on the two-dimensional van der Waals magnetic layer F; Or it may include the following steps: S1: Spin-coating photoresist onto an insulating substrate; S2: Electrode patterns are drawn using photolithography. S3: Electrode A and electrode G are deposited on the electrode pattern obtained in step S2. Electrode A and electrode G are located at both ends of the insulating surface of the insulating substrate and do not contact each other. S4: Sequentially mechanically peel off or deposit a two-dimensional van der Waals magnetic layer B, a two-dimensional van der Waals barrier layer C, a two-dimensional van der Waals barrier layer D, and a two-dimensional van der Waals magnetic layer F on an insulating substrate; the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate, and it is in contact with electrode A but not with electrode G; a portion of the two-dimensional van der Waals barrier layer C is located on top of the two-dimensional van der Waals magnetic layer B, and the portion of the two-dimensional van der Waals barrier layer C other than the top portion of the two-dimensional van der Waals magnetic layer B is located on the insulating substrate, and it is not in contact with electrode G; the two-dimensional van der Waals barrier layer D is located on the surface of the two-dimensional van der Waals barrier layer C, and it is not in contact with electrode G; the two-dimensional van der Waals magnetic layer F is located on top of the two-dimensional van der Waals barrier layer D, and one end is in contact with electrode G, thus obtaining a two-dimensional full van der Waals magnetic tunnel junction.

7. The method for preparing a two-dimensional full van der Waals magnetic tunneling junction based on a multi-layer barrier layer as described in claim 2 or 4, characterized in that, Includes the following steps: (1) Electrode A is deposited on an insulating substrate by vapor deposition; (2) Mechanically peel off or deposit two-dimensional van der Waals magnetic layer B, two-dimensional van der Waals barrier layer C, two-dimensional van der Waals barrier layer D, two-dimensional van der Waals barrier layer E and two-dimensional van der Waals magnetic layer F sequentially on electrode A; (3) Electrode G is deposited on the two-dimensional van der Waals magnetic layer F; Or it may include the following steps: S1: Spin-coating photoresist onto an insulating substrate; S2: Electrode patterns are drawn using photolithography. S3: Electrode A and electrode G are deposited on the electrode pattern obtained in step S2. Electrode A and electrode G are located at both ends of the insulating surface of the insulating substrate and do not contact each other. S4: Sequentially mechanically peel off or deposit a two-dimensional van der Waals magnetic layer B, a two-dimensional van der Waals barrier layer C, a two-dimensional van der Waals barrier layer D, a two-dimensional van der Waals barrier layer E, and a two-dimensional van der Waals magnetic layer F on an insulating substrate; the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate, and it is in contact with electrode A but not with electrode G; a portion of the two-dimensional van der Waals barrier layer C is located on top of the two-dimensional van der Waals magnetic layer B, and the portion of the two-dimensional van der Waals barrier layer C other than the top portion of the two-dimensional van der Waals magnetic layer B is located on the surface of the insulating substrate, and it is not in contact with electrode G; the two-dimensional van der Waals barrier layer D is located on the surface of the two-dimensional van der Waals barrier layer C, and it is not in contact with electrode G; the two-dimensional van der Waals barrier layer E is located on top of the two-dimensional van der Waals barrier layer E, and one end is in contact with electrode G, thus obtaining a two-dimensional full van der Waals magnetic tunnel junction.

8. The method for preparing a two-dimensional full van der Waals magnetic tunnel junction based on a multi-layer barrier layer as described in claim 6 or 7, characterized in that, The deposition method is chemical vapor deposition, molecular beam epitaxy, or magnetron sputtering.

9. The method for preparing a two-dimensional full van der Waals magnetic tunnel junction based on a multi-layer barrier layer as described in claim 6 or 7, characterized in that, The insulating substrate is SiO2, Al2O3, GaAs, polyimide, or fluorinated mica.

10. The method for preparing a two-dimensional full van der Waals magnetic tunnel junction based on a multi-layer barrier layer as described in claim 6 or 7, characterized in that, Electrode A and electrode G are each independently selected from metal electrodes Au, Cr, Pt, Al, Cu or Ti.

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