Development And Application Research Of Magneto-Optical Parameter Analysis System Based On Spectroscopic Ellipsometry

After the information technology revolution,countries all over the world have realized the importance of material technology innovation to national technological progress,economic development and national defense security.Magneto-optical materials,as a key research field in the revolution of materials technology,play an important role in the fields of magnetic random-access memories,magneto-optical sensor and spintronics by virtue of their unique physical properties.Magneto-optical materials can change their properties in the process of synthesis and preparation according to different application requirements.In this case,the feasibility and high efficiency of the characterization of their magneto-optical properties have become one of the factors restricting the development of magneto-optical materials.In order to meet the challenges brought by the development of magneto-optical materials,this paper designs and builds a spectroscopic ellipsometry-based system for the analysis of optical parameters in magnetics,and develops and applies it around its development.Firstly,this thesis describes the basic principles of magneto-optical Kerr effect and ellipsometry techniques.Based on the basic theories of magneto-optical Kerr effect and ellipsometry measurement,the theoretical model of magneto-optical ellipsometry measurement under longitudinal Kerr effect of bulk materials,monolayer and multilayer films,which provides theoretical support for the design and development of the system.Secondly,the design requirements of the magneto-optical parameter analysis system are proposed.According to the design requirements,the device selection,design and construction of the light source system,optical path system,magnetic system are completed.The process of experimental and matters for attention of magneto-optical parameter testing of this system are introduced in detail.The accuracy of the system was studied and analyzed by measuring the refractive index,extinction coefficient and complex magneto-optical coupling coefficient of Permalloy.Finally,the research on the application of the magneto-optical parameter analysis system in the testing and analysis of the magneto-optical coupling coefficient of thin film materials was carried out.The system was used to test and analyze the magneto-optical properties of CoFeB thin film.According to magneto-optical ellipsometry theory of monolayer film,the experimental data are fitted by the least-squares method,and the results obtained from the fitting were programmed and calculated to obtain the spectral curves of refractive index,extinction coefficient and complex magneto-optical coupling coefficient of CoFeB thin films,which provide a reference for the application and development of CoFeB magnetic tunnel junction materials;the analysis of the magneto-optical ellipsometry of Ta/Pt/Co/Pt thin films were analyzed by magneto-optical ellipsometry tests,and the spectral curves of their complex magneto-optical coupling coefficients were obtained by fitting the experimental data based on the theory of magneto-optical ellipsometry of multilayer films,and the related mechanisms were explained,providing a new research idea for spin-orbit moment materials.