Rare earth doped perpendicular magnetic anisotropy oxide film and preparation method thereof
By preparing LaxNi1-xCo2O4 thin films on MgAl2O4 substrates, the lattice distortion problem caused by lanthanum doping was solved, and the preparation of high-performance rare-earth doped oxide thin films was realized, which are suitable for high-density magnetic storage devices and low-cost large-scale production.
Patent Information
- Application Number
- CN202511572166.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-30
- Publication Date
- 2026-01-23
AI Technical Summary
Lanthanum-doped spinel oxide films suffer from lattice distortion and performance degradation, making it difficult to prepare high-performance rare-earth-doped vertical magnetic anisotropic oxide films.
Rare earth-doped vertical magnetic anisotropic oxide films were prepared on MgAl2O4(001) substrates using LaxNi1-xCo2O4(001) thin film layers via magnetron sputtering and ceramic sintering processes. The crystal orientation and compositional uniformity of the films were controlled, and in-situ annealing was performed.
Rare-earth-doped oxide thin films with high Curie temperature, robust room-temperature vertical magnetic anisotropy, and excellent conductivity were prepared, making them suitable for high-density magnetic storage devices, with low cost and suitability for large-scale production.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of hard magnetic rare earth element-doped oxide thin film materials, and particularly to a rare earth-doped vertical magnetic anisotropic oxide thin film and its preparation method. Background Technology
[0002] With the rapid development of science and technology, the application fields of semiconductor materials are constantly expanding, especially in optoelectronic devices, microelectronic devices, and energy conversion and storage, where the performance requirements for semiconductor thin film materials are becoming increasingly stringent. Spinel oxides, due to their excellent thermal stability, electrical properties, magnetic properties, and good catalytic performance, occupy an important position among various advanced materials. Spinel oxides generally possess characteristics such as structural stability and good ionic conductivity, and are widely used in catalysis, lithium batteries, battery anodes, gas sensors, optoelectronic devices, and many other fields. Therefore, researching their doping modification techniques, especially the doping of rare earth elements, has become an important direction for improving the performance of spinel oxide thin films.
[0003] Rare earth elements, due to their unique electronic structures, are widely used to improve the electrical conductivity, magnetic properties, and catalytic performance of materials. Lanthanum (La), as one of the rare earth elements, is receiving increasing attention in materials science. Lanthanum possesses a large ionic radius and high electronegativity, making it suitable as a dopant in certain oxide materials to effectively modulate their electrical, magnetic, and optical properties.
[0004] Spinel oxides are typically represented by the chemical formula AB₂O₄ (where A and B are metal ions). In this structure, metal ion A occupies octahedral positions, B ions occupy tetrahedral positions, and oxygen ions are located between these metal ions. To ensure the stability of the spinel structure, the chemical properties and ionic radii of the A and B ions must be compatible. Lanthanum has a relatively large ionic radius (La). 3+ The ionic radius of the metal ion is approximately 1.16 Å, while the metal ion in spinel oxides (such as NiCo2O4) is... 2+ and Co 3+ Lanthanum ions have a relatively small ionic radius. The larger size of lanthanum ions can lead to lattice distortion, affecting the stability of the spinel structure. Therefore, when doping with La, it is necessary to overcome the lattice strain caused by this size mismatch. Furthermore, the electronic structure and oxidation state characteristics of lanthanum also increase the complexity of the doping process. Lanthanum ions are generally trivalent (La... 3+ Its electron cloud is relatively loose, which may lead to certain ion migration and lattice distortion during the doping process, thus affecting the material's conductivity, magnetism and other properties.
[0005] Although lanthanum doping of spinel oxide films presents certain challenges, appropriate lanthanum doping can improve the material's performance to some extent. Firstly, lanthanum doping can effectively modulate the electrical properties of spinel oxide films. Due to lanthanum's large ionic radius, its doping leads to lattice expansion, thus affecting the material's conductivity. In some cases, appropriate lanthanum doping can introduce additional charge carriers, enhancing the material's conductivity and consequently improving its performance in electronic devices.
[0006] Lanthanum can also influence the crystal defect behavior of spinel oxide films. Lanthanum doping may introduce new defect states or help optimize existing defect structures, thereby improving catalytic activity. For example, in catalytic reactions, lanthanum-doped spinel oxide films exhibit high catalytic activity and strong stability, showing promising application prospects, especially in oxygen reduction and nitrogen reduction reactions.
[0007] In summary, lanthanum-doped semiconductor oxide thin films have become a research hotspot for next-generation high-performance magnetic materials due to their excellent perpendicular magnetic anisotropy, good magnetic stability, and potential for controlling electrical, optical, and thermal properties. With further research, lanthanum-doped semiconductor oxide thin films are expected to find wider applications in spintronics, magnetic storage, quantum computing, and other fields, driving new breakthroughs in technological development. Therefore, we propose a rare-earth-doped perpendicular magnetic anisotropy oxide thin film and its preparation method. Summary of the Invention
[0008] The main objective of this invention is to provide a rare-earth-doped vertical magnetic anisotropic oxide thin film and its preparation method, which can effectively solve the problems in the background art.
[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A rare-earth-doped vertically magnetically anisotropic oxide thin film having a (001) plane crystal orientation includes a substrate and a thin film layer, wherein the substrate is MgAl2O4 (001) and the thin film layer is La. x Ni 1-x Co2O4(001).
[0010] Preferably, the thin film layer La x Ni 1-x In Co2O4(001), the La doping amount x=0.05, under which the film exhibits a Curie temperature above room temperature, robust room temperature vertical magnetic anisotropy and optimal electrical conductivity, with a coercivity of 242 Oe.
[0011] Preferably, the thin film layer La x Ni 1-x The La doping amount in Co2O4(001) is x=0.1.
[0012] Preferably, a method for preparing a rare-earth-doped vertically magnetically anisotropic oxide thin film includes the following steps: S1. Preparation of ceramic target material: La is prepared by ceramic sintering process. 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 Co2O4 target material; S2. Substrate processing: Pre-treatment of the substrate; S3. Thin film formation: Thin films are deposited on a substrate using a target material through magnetron sputtering. The thickness of the thin film can be controlled by the sputtering time. S4. Annealing treatment: After the thin film deposition is completed, the film is annealed in situ and then cooled.
[0013] Preferably, La is prepared by ceramic sintering process. 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 The ceramic sintering process for Co2O4 targets adopts solid-state sintering. The ceramic targets are prepared using NiO powder, Co3O4 powder and La2O3 powder with a purity level of 4N.
[0014] Preferably, the specific steps for preparing the ceramic target material are as follows: NiO powder, Co3O4 powder and La2O3 powder were fed into a ball mill jar, and alcohol was added as a grinding aid. The mixture was wet-milled at 200 rpm for 40 minutes. The ball-milled raw material is fed into a muffle furnace and held at 750°C for 12 hours at a heating rate of 5°C per minute for the first sintering. After the first sintering, the powder was put back into the ball mill jar and dry-milled at 200 rpm for 20 minutes. Then, the binder was added and the powder was pressed into shape by pressing at 20 MPa for 15 minutes using a tablet press. The pressed sheet is fed into a muffle furnace and held at 750°C for 12 hours at a heating rate of 5°C per minute for a second sintering. The sintered product is then polished to obtain the desired ceramic target material.
[0015] Preferably, the substrate is a single-crystal MgAl2O4 substrate with a (001) plane crystal orientation, which is 5x5mm in size and 1mm in thickness.
[0016] Preferably, the pretreatment steps for the substrate include immersing the substrate in alcohol, cleaning it with an ultrasonic cleaner for 3-5 minutes, drying it with nitrogen, and then placing it into the deposition chamber of the magnetron sputtering system.
[0017] Preferably, a vacuum is evacuated before magnetron sputtering to ensure that the vacuum level inside the cavity is not less than 10. -4 Pa, introduce a 1:1-2 argon / oxygen mixture, adjust the opening of the baffle valve to maintain the gas pressure at 1Pa-5Pa, then heat the substrate to 350℃-500℃, and keep the baffle closed for 2 hours of pre-sputtering; During magnetron sputtering, the oxidation level and lattice defects of the thin film are controlled by controlling the atmosphere. During magnetron sputtering, the RF power supply is turned on first, and the baffle is kept closed for pre-sputtering, which lasts for 5 minutes. After pre-sputtering, the baffle is opened to start sputtering. The magnetron sputtering power is 40W and the rate is 18nm / hour.
[0018] During magnetron sputtering, the compositional uniformity and crystal quality of the thin film are optimized by adjusting the sputtering energy and frequency, as well as the appropriate temperature of the target and the angle of the substrate.
[0019] Preferably, the in-situ annealing time is 30-60 min, the temperature is in the range of 350-500℃, and the oxygen pressure is 1 Pa-5 Pa.
[0020] By altering the composition, surface state, and structure of the MgAl2O4 substrate, stress regulation of the thin film can be achieved, thereby optimizing coercivity and conductivity.
[0021] Compared with the prior art, the rare earth-doped vertical magnetic anisotropic oxide thin film and its preparation method of the present invention have the following beneficial effects: Firstly, this invention describes a rare-earth-doped vertical magnetic anisotropic oxide thin film and its preparation method. This method overcomes the lattice strain caused by ion radius size mismatch by doping lanthanum into the crystal structure of spinel oxide NiCo2O4. The preparation process employs radio frequency magnetron sputtering with lanthanum... 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 Using Co2O4 target material, a series of La materials with different thicknesses were prepared. 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 The resulting Co2O4 thin film exhibits robust perpendicular magnetic anisotropy, a Curie temperature above room temperature, and excellent electrical conductivity. Its anomalous Hall resistivity is 3.64 μΩ·cm at a thickness of 8.1 nm, which enhances the film's performance and broadens its applicability.
[0022] Secondly, this invention describes a rare-earth-doped vertical magnetic anisotropic oxide thin film and its preparation method, which has significant application potential in the field of magnetic storage. It can provide new possibilities for the development of high-density, high-speed and low-power magnetic storage devices, and provide new ideas for rare-earth doping to regulate the performance of oxide semiconductor thin films. At the same time, this method has the advantage of low material cost, which is conducive to large-scale preparation and industrial production, and has good application prospects. Attached Figure Description
[0023] Figure 1 This invention relates to a rare-earth-doped vertical magnetic anisotropic oxide thin film, La. x Ni 1-x Schematic diagram of the structure of Co2O4 (x=0.05, 0.1) thin film; Figure 2 This invention relates to a rare-earth-doped vertical magnetic anisotropic oxide thin film, La. x Ni 1-x X-ray diffraction patterns of Co2O4 (x=0.05, 0.1) thin films; Figure 3 The La with a thickness of 20.1 nm provided in this embodiment of the invention 0.05 Ni 0.95 Anomalous Hall curves of Co2O4 thin films as a function of temperature; Figure 4 The La with a thickness of 20.1 nm provided in this embodiment of the invention 0.1 Ni 0.9 Anomalous Hall curves of Co2O4 thin films as a function of temperature; Figure 5 This is a flowchart of a method for preparing rare earth-doped vertical magnetic anisotropic oxide thin films according to the present invention. Detailed Implementation
[0024] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.
[0025] A rare-earth-doped vertically magnetically anisotropic oxide thin film having a (001) plane crystal orientation includes a substrate and a thin film layer, wherein the substrate is MgAl2O4 (001) and the thin film layer is LaxNi. 1-x Co2O4(001), thin film layer La x Ni 1-x Co2O4 is epitaxially grown on a MgAl2O4 substrate, specifically a La substrate with a thickness of 2-20 nm and a (001) orientation. x Ni 1-x Single-crystal thin film layers of Co2O4 (x=0.05, 0.1).
[0026] thin film layer La x Ni 1-x In Co2O4(001), the La doping amount x=0.05, under which the film exhibits a Curie temperature above room temperature, robust room temperature vertical magnetic anisotropy and optimal electrical conductivity, with a coercivity of 242 Oe.
[0027] thin film layer LaxNi 1-x The La doping amount in Co2O4(001) is x=0.1.
[0028] A method for preparing a rare-earth-doped vertically magnetically anisotropic oxide thin film includes the following steps: S1. Preparation of ceramic target material: La is prepared by ceramic sintering process. 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 Co2O4 target material; La was prepared by ceramic sintering process. 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 The ceramic sintering process for Co2O4 target material adopts solid-state sintering method. The ceramic target material is prepared by NiO powder, Co3O4 powder and La2O3 powder with a purity level of 4N. The specific steps for preparing ceramic targets are as follows: NiO powder, Co3O4 powder and La2O3 powder were fed into a ball mill jar, and alcohol was added as a grinding aid. The mixture was wet-milled at 200 rpm for 40 minutes to ensure that the raw materials were mixed evenly. The ball-milled raw material is fed into a muffle furnace and held at 750°C for 12 hours at a heating rate of 5°C per minute for the first sintering. After the first sintering, the powder was put back into the ball mill jar and dry-milled at 200 rpm for 20 minutes. Then, the binder was added and the powder was pressed into shape by pressing at 20 MPa for 15 minutes using a tablet press. The pressed sheet is fed into a muffle furnace and held at 750°C for 12 hours at a heating rate of 5°C per minute for a second sintering. The sintered product is then polished to obtain the desired ceramic target material. S2. Substrate processing: Pre-treatment of the substrate; The substrate is a MgAl2O4 substrate commonly used in commercial microwave devices. The substrate is a single-crystal MgAl2O4 substrate with (001) plane crystal orientation, with a size of 5x5mm and a thickness of 1mm. The pretreatment steps for the substrate include immersing the substrate in alcohol, cleaning it with ultrasonic cleaning equipment for 3-5 minutes, drying it with nitrogen gas, and then placing it into the deposition chamber of the magnetron sputtering system. S3. Thin film formation: Thin films are deposited on a substrate using a target material through magnetron sputtering. The thickness of the thin film can be controlled by the sputtering time. Before magnetron sputtering, a vacuum is evacuated. During evacuation, the magnetron sputtering system deposition chamber is closed, the mechanical pump is started, and the valve connecting the mechanical pump and the chamber is opened to evacuate. A resistance gauge is then used to measure the internal gas pressure of the chamber. The pressure is lowered to 1×10⁻⁶. 1 After the pressure drops below 1 Pa, close the connecting valve, open the molecular pump isolation valve, start the molecular pump, and fully open the molecular pump gate valve to connect the molecular pump to the chamber. When the pressure drops to 1 × 10⁻⁶, close the connecting valve, open the molecular pump isolation valve, start the molecular pump, and fully open the molecular pump gate valve to connect the molecular pump to the chamber. -1 At Pa, the ionization gauge is opened, and the vacuum level inside the cavity is not less than 10. -4 At a pressure of 1 Pa, an argon / oxygen mixture of 1:1-2 is introduced. The opening of the baffle valve is adjusted to maintain the gas pressure at 1 Pa-5 Pa. The substrate is then heated to 350℃-500℃, and the baffle is kept closed for 2 hours of pre-sputtering. After pre-sputtering, impurities on the target surface are removed. A ferrimagnetic reference layer is grown on the substrate after pre-sputtering. During magnetron sputtering, the oxidation level and lattice defects of the thin film are controlled by controlling the atmosphere. During magnetron sputtering, the RF power supply is turned on first, and the baffle is kept closed for pre-sputtering, which lasts for 5 minutes. After pre-sputtering, the baffle is opened to start sputtering. The magnetron sputtering power is 40W and the rate is 18nm / hour.
[0029] During magnetron sputtering, the compositional uniformity and crystal quality of the thin film are optimized by adjusting the sputtering energy and frequency, as well as the appropriate temperature of the target and the angle of the substrate. During sputtering, the film thickness does not exceed 100 nm, and the consumption of sputtering target material is minimal per growth cycle. The nanoscale films meet the requirements for miniaturization and integration. Furthermore, radio frequency magnetron sputtering is currently the preferred method for mass production in industry, and the growth temperature of 350℃-500℃ has good process compatibility, which is very suitable for the requirements of today's industrial mass production.
[0030] S4. Annealing treatment: After the thin film deposition is completed, the film is annealed in situ and then cooled.
[0031] The in-situ annealing time is 30-60 minutes, the temperature is in the range of 350-500℃, and the oxygen pressure is 1Pa-5Pa.
[0032] By altering the composition, surface state, and structure of the MgAl2O4 substrate, stress regulation of the thin film can be achieved, thereby optimizing coercivity and conductivity.
[0033] Further description based on the actual production data below: A method for preparing rare-earth-doped vertically magnetic anisotropic oxide thin films, the process steps of which are as follows: La was prepared using standard ceramic sintering process. x Ni 1-x The target material of Co2O4 (x=0.05, 0.1) was prepared by wet milling NiO powder, Co3O4 powder, and La2O3 powder in a ball mill jar with alcohol as a grinding aid at 200 rpm for 40 min, according to the stoichiometric ratio. The mixture was then sintered for the first time in a muffle furnace at 750°C for 12 hours with a heating rate of 5°C per minute. The pre-sintered powder was then dry-milled again in a ball mill jar at 200 rpm for 20 min, and a binder was added. The mixture was then pressed into shape using a tablet press at 20 MPa for 15 min. Finally, the target material was sintered for the second time in a muffle furnace at 750°C for 12 hours with a heating rate of 5°C per minute to obtain the desired ceramic target material. Immerse the MgAl2O4 substrate in alcohol and clean it with an ultrasonic cleaner for 3-5 minutes. After cleaning, dry the MgAl2O4 substrate with nitrogen and immediately place it into the deposition chamber of the magnetron sputtering system.
[0034] Close the magnetron sputtering system deposition chamber, start the mechanical pump, open the valve connecting the mechanical pump and the chamber to evacuate the system, and start the resistance gauge to measure the internal pressure of the chamber. Wait for the pressure to drop to 1×10⁻⁶. 1 After the pressure drops below 1 Pa, close the connecting valve, open the molecular pump isolation valve, start the molecular pump, and fully open the molecular pump gate valve to connect the molecular pump to the chamber. When the pressure drops to 1 × 10⁻⁶, close the connecting valve, open the molecular pump isolation valve, start the molecular pump, and fully open the molecular pump gate valve to connect the molecular pump to the chamber. -1 At a pressure of Pa, open the ionization gauge. When the vacuum reaches 1 × 10⁻⁶ Pa, [the vacuum level is then adjusted]. -4 After Pa, a 1:1 argon / oxygen (Ar / O2) mixture is introduced, and the opening of the gate valve is adjusted to maintain the gas pressure at 1 Pa. Then, the substrate is heated to 350°C. La2O4 was deposited on a MgAl2O4(001) single crystal substrate by magnetron sputtering. x Ni 1-x Co2O4 (x=0.05, 0.1) targets were used for thin film deposition. First, the power supply was adjusted, the RF power supply was started, and the baffle was kept closed for pre-sputtering for 5 minutes. After pre-sputtering, the baffle was opened to begin sputtering, and the film thickness was controlled by adjusting the sputtering time; specifically, the magnetron sputtering power was 40W, and the sputtering rate was 18nm / hour. During magnetron sputtering, the compositional uniformity and crystal quality of the thin film can be optimized by adjusting the sputtering energy, the appropriate temperature of the target, and the angle of the substrate. After the thin film deposition is complete, it is kept at 380℃ for 30 minutes to make its composition more uniform, and then cooled to room temperature.
[0035] In La 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 An anomalous Hall effect was observed in a Co2O4 thin film, a hallmark of perpendicular magnetic anisotropy. A La film with a thickness of 20.1 nm... 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 Typical hysteresis loops of the Hall resistance of Co2O4 thin films at different temperatures are as follows: Figure 3 As shown. The temperature at which the anomalous Hall effect disappears can be considered the Curie temperature of the sample. Obviously, for a 20.1 nm thick La... 0.05 Ni 0.95 The Curie temperature of Co₂O₄ thin films reaches a high level of 360 K, which is crucial for spintronics applications and device miniaturization. This robust perpendicular magnetic anisotropy is rarely observed in nanometer-thick oxide films. For the same thickness (20.1 nm), La… 0.1 Ni 0.9 Although Co2O4 also exhibits robust perpendicular magnetic anisotropy, its Curie temperature is only around 300K, compared to La of the same thickness. 0.05 Ni 0.95 The Co2O4 film showed a decrease, which may be due to the fact that increasing the lanthanum doping concentration exacerbated the lattice distortion of NiCo2O4, leading to a weakening of its magnetic properties.
[0036] In summary, this invention provides a rare-earth-doped hard magnetic oxide semiconductor thin film with robust perpendicular magnetic anisotropy and a high Curie temperature, the material composition of which is La. x Ni 1-x The Co2O4 (x=0.05, 0.1) thin film with a crystal orientation of (001) was prepared using MgAl2O4 (001) single crystal as a substrate. The resulting thin film exhibits a high Curie temperature and excellent conductivity. This provides a novel high Curie temperature oxide semiconductor thin film for magnetic storage and magnetic sensing applications.
[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.
Claims
1. A rare-earth-doped vertical magnetic anisotropic oxide thin film, characterized in that, It has a (001) plane crystal orientation and includes a substrate and a thin film layer, wherein the substrate is MgAl2O4 (001) and the thin film layer is La. x Ni 1-x Co2O4(001).
2. The rare-earth-doped vertical magnetic anisotropic oxide thin film according to claim 1, characterized in that: The thin film layer La x Ni 1-x The La doping amount in Co2O4(001) is x=0.
05.
3. A rare-earth-doped vertical magnetic anisotropic oxide thin film according to any one of claims 1-2, characterized in that: The thin film layer La x Ni 1-x The La doping amount in Co2O4(001) is x=0.
1.
4. The method for preparing a rare-earth-doped vertical magnetic anisotropic oxide thin film according to claim 3, characterized in that: Includes the following steps: S1. Preparation of ceramic target material: La is prepared by ceramic sintering process. 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 Co2O4 target material; S2. Substrate processing: Pre-treatment of the substrate; S3, Thin film formation; Thin films are deposited on a substrate using a target material via magnetron sputtering. S4. Annealing treatment: After the thin film deposition is completed, the film is annealed in situ and then cooled.
5. The method for preparing a rare-earth-doped vertical magnetic anisotropic oxide thin film according to claim 4, characterized in that: La was prepared by ceramic sintering process. 0.05 Ni 0.95 Co2O4 and La 0.1 Ni 0.9 The ceramic sintering process for Co2O4 targets adopts solid-state sintering. The ceramic targets are prepared using NiO powder, Co3O4 powder and La2O3 powder with a purity level of 4N.
6. The method for preparing a rare-earth-doped vertical magnetic anisotropic oxide thin film according to claim 4, characterized in that: The specific steps for preparing the ceramic target material are as follows: NiO powder, Co3O4 powder and La2O3 powder were fed into a ball mill jar, and alcohol was added as a grinding aid. The mixture was wet-milled at 200 rpm for 40 minutes. The ball-milled raw material is fed into a muffle furnace and held at 750°C for 12 hours at a heating rate of 5°C per minute for the first sintering. After the first sintering, the powder was put back into the ball mill jar and dry-milled at 200 rpm for 20 minutes. Then, the binder was added and the powder was pressed into shape by pressing at 20 MPa for 15 minutes using a tablet press. The pressed sheet is fed into a muffle furnace and held at 750°C for 12 hours at a heating rate of 5°C per minute for a second sintering. The sintered product is then polished to obtain the desired ceramic target material.
7. The rare-earth-doped vertical magnetic anisotropic oxide thin film and its preparation method according to claim 6, characterized in that: The substrate is a single-crystal MgAl2O4 substrate with a (001) plane crystal orientation, which is 5x5mm in size and 1mm in thickness.
8. The method for preparing a rare-earth-doped vertically magnetically anisotropic oxide thin film according to claim 7, characterized in that: The pretreatment steps for the substrate include immersing the substrate in alcohol, cleaning it with ultrasonic cleaning equipment for 3-5 minutes, drying it with nitrogen gas, and then placing it into the deposition chamber of the magnetron sputtering system.
9. The method for preparing a rare-earth-doped vertical magnetic anisotropic oxide thin film according to claim 8, characterized in that: A vacuum is evacuated before magnetron sputtering to ensure a vacuum level of no less than 10⁻⁶. -4 Pa, introduce a 1:1-2 argon / oxygen mixture, adjust the opening of the baffle valve to maintain the gas pressure at 1Pa-5Pa, then heat the substrate to 350℃-500℃, and keep the baffle closed for 2 hours of pre-sputtering; During magnetron sputtering, the RF power supply is turned on first, and the baffle is kept closed for pre-sputtering, which lasts for 5 minutes. After pre-sputtering, the baffle is opened to start sputtering. The magnetron sputtering power is 40W and the rate is 18nm / hour.
10. The method for preparing a rare-earth-doped vertical magnetic anisotropic oxide thin film according to claim 9, characterized in that: The in-situ annealing time is 30-60 minutes, the temperature is in the range of 350-500℃, and the oxygen pressure is 1Pa-5Pa.