CN-117265483-B - High-coercivity hard magnetic oxide semiconductor film with perpendicular magnetic anisotropy and preparation method thereof

Abstract

The invention discloses a high coercivity hard magnetic oxide semiconductor film with perpendicular magnetic anisotropy and a preparation method thereof, wherein a process for alternately preparing a gradient film by multiple targets is adopted, and NiFeO-xFexO-NiCo 2O4 gradient films are prepared by alternately sputtering target materials of NiFeO and NiCo2O 4. Experimental results show that the obtained film has coercive force as high as 1T and good electric conductivity, and abnormal Hall resistivity reaches 52.5 mu omega cm. The preparation method has the advantages of simplicity and lower cost, and provides new possibility for the research and development of the magnetic memory device. The method has important application potential for realizing the magnetic memory device with high density, high speed and low power consumption, and is beneficial to promoting the development and application of the magnetic memory technology.

Inventors

• ZHOU KE
• JIN QINGREN
• LU BAIHUA
• WANG XIAOMING
• MO ZHIYUE
• QIN LIWEN

Assignees

• 广西电网有限责任公司电力科学研究院

Dates

Publication Date

20260505

Application Date

20230730

Claims (2)

1. 1. A high coercivity hard magnetic oxide semiconductor film having perpendicular magnetic anisotropy is characterized by comprising, A substrate MgAl 2 O 4 , a seed layer NiCo 2 O 4 and a film gradient layer NiCo 2-x Fe x O 4 ; The preparation method of the film gradient layer NiCo 2-x Fe x O 4 comprises the steps of preparing targets of NiFe 2 O 4 and NiCo 2 O 4 through a standard ceramic sintering process; Depositing a film on a MgAl 2 O 4 (001) single crystal substrate by adopting a NiCo 2 O 4 / NiFe 2 O 4 target alternately by a pulse laser deposition or magnetron sputtering method, and controlling the thickness of the film by pulse/sputtering time; After the film deposition is finished, in-situ annealing is carried out for 30-60 min, so that the components of the film are more uniform, and then cooling is carried out; The method comprises the steps of adopting a NiCo 2 O 4 target to deposit a film layer, switching to a NiFe 2 O 4 target after a certain thickness, switching to a NiCo 2 O 4 target according to the result of thickness detection or calculation, controlling the component change of Co and Fe in the film, and gradually transitioning the doping amount of Fe from 0 to xmax, wherein the value range of xmax is 0.5-1; Wherein, the crystal orientation of the film is (001), and MgAl 2 O 4 (001) single crystal is taken as a substrate.
2. 2. The film of claim 1, wherein the in-situ annealing is performed at a temperature ranging from 350 to 500 ℃ and an oxygen pressure ranging from 1Pa to 20Pa for 30 to 60 minutes.

Description

High-coercivity hard magnetic oxide semiconductor film with perpendicular magnetic anisotropy and preparation method thereof Technical Field The invention belongs to the field of hard magnetic oxide film materials, and particularly relates to a high-coercivity hard magnetic oxide semiconductor film with perpendicular magnetic anisotropy and a preparation method thereof. Background Both the field of magnetic storage and the field of magnetic sensitivity place a high demand on hard magnetic materials with perpendicular magnetic anisotropy. Magnetic memory devices, such as hard disk drives and Magnetic Random Access Memories (MRAM), require high coercivity hard magnetic materials to achieve stable magnetic memory states, while the magnetic sensor field, especially the new generation of perpendicular TMR structures, requires highly stable perpendicular pinning layers, which requires the development of advanced perpendicular hard magnetic materials. However, conventional perpendicular magnetic anisotropic hard magnetic materials, such as cobalt alloys and iron cobalt boron, have some limitations, such as high cost, complex manufacturing processes, and high magnetic exchange coupling fields. Compared with a metal hard magnetic material, the oxide magnetic material has the advantages of high spin polarization rate, high impedance, capability of forming a better epitaxial structure with the MgO tunneling layer, theoretical high magnetic resistance and the like. Based on composition and strain regulation, the coercivity of the oxide magnetic material can be designed more conveniently to meet the requirements of different applications. However, current oxide hard magnetic materials still have certain limitations in terms of coercivity and conductivity. Conventional oxide hard magnetic materials tend to have a lower coercivity and higher resistivity, which limits their use in the field of high density magnetic storage. Therefore, there is an urgent need for a method for producing an oxide hard magnetic material capable of improving coercive force and conductivity. Improving the coercivity of oxide hard magnetic materials, particularly in the vertical direction, can significantly improve the performance and stability of the magnetic memory device. In addition, the conductivity of the oxide hard magnetic material is improved, so that the oxide hard magnetic material has lower resistivity, the power consumption of the magnetic memory device can be reduced, and the data reading and writing speed can be improved. Therefore, the research and development of a method for preparing the oxide hard magnetic material with perpendicular magnetic anisotropy, high coercivity and conductivity has important scientific and application values. Disclosure of Invention This section is intended to outline some aspects of embodiments of the application and to briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section as well as in the description of the application and in the title of the application, which may not be used to limit the scope of the application. The present invention has been made in view of the above and/or problems occurring in the prior art. It is therefore an object of the present invention to overcome the deficiencies in the prior art and to provide a high coercivity hard magnetic oxide semiconductor thin film having perpendicular magnetic anisotropy. In order to solve the technical problems, the invention provides a technical scheme that the high coercivity hard magnetic oxide semiconductor film with perpendicular magnetic anisotropy comprises, A substrate MgAl2O4 (101), a seed layer NiCo2O4 (102) and a film gradient layer NiCo2-xFexO4 (103); The value of the doping amount x of the Fe of the NiCo2-xFexO4 gradually transits from the minimum value xmin to the maximum value xmax along with the thickness of the film from the substrate to the surface, the value range of xmin is 0-0.1, and the value range of xmax is 0.5-1; The crystal orientation of the film is (001), and MgAl2O4 (001) single crystal is taken as a substrate. As a preferable scheme of the film, when the Fe doping amount x=0, the film shows the lowest coercive force, weak perpendicular magnetic anisotropy and optimal conductivity, and the coercive force is generally not higher than 100Gs; with the increase of xmax, the saturation magnetization and the coercive force of the film are gradually increased, and the coercive force exceeds 10000Gs at proper thickness when xmax=1, wherein the rectangular ratio of the film is always higher than 100%; When xmax=xmin=1, i.e., there is no gradient in the thin film, the conductivity of the thin film is poor and the coercive force is lower than that of the gradient thin film. It is still another object of the present invention to overcome the disadvantages of the prior art and to provide a method for preparing a high coercivity hard magnetic oxide semiconductor thin film havi