The Characterization Methods Of Magneto-optical Materials Based On Magneto-optical Kerr Effect

The magneto-optical devices such as magneto-optical switches,magneto-optical memories,magneto-optical sensors,and spin electronics are widely used in the fields of information,medical care and national defense,hence the demand for high-performance magneto-optical materials is increasing.To improve the performance of existing magneto-optical materials and to explore new types of magneto-optical materials we need to find efficient magneto-optical material characterization methods.Various magneto-optical characterization techniques based on magneto-optical effect are used to characterize the magneto-optical performance of the magneto-optical material by measuring the magneto-optical response of the magneto-optical material device to realize the non-destructive testing of the material device.In addition,the magneto-optical characterization techniques have high test precision,high sensitivity,High temporal resolution,high-strength magnetic field compatibility,etc.,so the magneto-optical characterization techniques can provide advanced measurement tools for the search of magneto-optical materials.In this paper,the characterization methods of magneto-optical materials based on magneto-optical Kerr effect are discussed.Firstly,the analytical method for longitudinal Kerr effect of anisotropic materials is discussed.The longitudinal Kerr effect theory model of anisotropic materials is constructed.The longitudinal Kerr rotation expression of anisotropic materials is obtained by solving the Fresnel equations with the boundary matrix of the medium and the transmission matrix of the medium.The magneto-optical Kerr properties of anisotropic Co films and isotropic Co films were analyzed and compared using the derived formulas.The result show that the anisotropic Co films have better magneto-optical properties than isotropic Co films,which provide a theoretical basis for the fabrication and design of magneto-optical devices based on Co films.Then the magneto-optical properties of CoFeB films were measured by magneto-optical ellipsometry system.The optical constants and the magneto-optical coupling coefficients were measured by the magneto-optical ellipsometry system.At last,the configuration of two kinds of magneto-optical Kerr microscopy and the selection methods of important components such as light source,objective lens and CCD camera are discussed.Also a method is proposed to optimize the domain visibility in Kerr microscopy by optimizing the azimuth angle of the polarizer.It provides an advanced measurement tool for intuitive understanding of the magnetic domain structure of the magnetic material so as to understand the nature of the magnetic material.