Research On In-Situ Mueller Matrix Ellipsometric Characterization Of Magneto-optical Properties Of Magnetic Films

With the development of magneto-optical devices towards high precision,high integration,low loss,ultra-fast transmission and so on,the performance requirements of materials are constantly improved.The magnetic thin film with high performance represented by spinel ferrite have attracted much attention because of their unique magnetooptic characteristics.The study of optical and magnetic properties of magnetic thin film materials with different properties and thickness can provide strong support for the regulation and optimization of magnetic thin film materials and provide theoretical basis for improving the performance of magneto-optical devices.Therefore,it is of great significance to accurately characterize the magneto-optical properties of magnetic thin film materials.Based on magneto-optic Kerr effect and ellipsometry,magneto-optic ellipsometry in situ characterization technology has many advantages,such as high precision,high sensitivity,nondestructive measurement,abundant measurement information and so on,which can meet the requirements of magneto-optical characterization of magnetic thin film materials.In view of the limitation of the current magneto-optical ellipsometry in measuring the thickness of objects,this paper proposes a magneto-optic ellipsometry in situ characterization method suitable for various types of magnetic film materials.The main research work and innovation points include:Firstly,the optical characteristic model based on magneto-optic Kerr effect and Fresnel interference theory is established.Among them,the modeling method of single-layer magnetic thin film material is studied,and the modified optical characteristic model of magnetic material is proposed.The model fully considers the phase change of light propagating in the film and breaks the thickness limitation of the existing method.In order to achieve accurate characterization of magnetic thick film magneto-optic characteristics.Then,taking full advantage of the measurement information of the Muller matrix ellipsometer,the spectral magneto-optic parameter extraction method based on Muller matrix is proposed,and the optical and magnetic properties of isotropic magnetic films are obtained simultaneously in a single measurement.After that,the proposed single-layer thin film magneto-optic ellipsometry method is used to realize the extraction of magneto-optic parameters of Ni film,and the calculation results are compared with those reported in the literature and with the existing methods,thus verifying the effectiveness,accuracy and applicability of this method.Finally,the nickel ferrate magnetic films with different thickness and substrate are measured and analyzed by the proposed method.The results verify the influence of thickness,substrate and other factors on the magnetic parameters of the materials.