Study On Temperature Dependent Dielectric Functions For Magnetic Metal Thin Films Based On Ellipsometric Spectrum

In recent years,magnetic materials,especially low-dimensional magnetic nanometer films,have become important components in magnetic storage,magnetic actuators of MEMS and magnetic sensors,and their magnetic properties often directly determine the performance of devices.In order to obtain the optical properties of magnetic materials at different ambient temperatures and analyze the temperature response characteristics of the optical properties of the materials.In this paper,the response of the dielectric function of Ni and Co metal films to temperature is systematically studied by means of spectral ellipsometry.The main research contents of this thesis are as follows:(1)The characteristics of magnetic metal thin films are analyzed,and according to the characteristics,the flow chart of spectral ellipticity analysis of magnetic metal thin films and the corresponding parameter analysis method are proposed.The Cu film and Ni film were taken as examples for comparative analysis.(2)The experiment of normal temperature ellipticity measurement of Ni and Co metal films under magnetic excitation and non-magnetic excitation was completed to illustrate the influence of external magnetic excitation on the optical properties of Ni and Co films under normal temperature.Through the analysis of experimental results,it is found that at room temperature of 300 K,with the excitation of external magnetic field,Ni and Co thin films change from paramagnetic state to ferromagnetic state,and their dielectric functions also change accordingly.(3)The elliptic measurement experiment of Ni and Co metal films under the condition of non-magnetic excitation under the temperature change of 300K?900K was completed to illustrate the effect of temperature on the optical properties of paramagnetic Ni and Co films.The results showed that the elliptic parameters of Ni films under non-magnetic excitation shifted upward with the temperature increase within 300K?600K,and downwards with the temperature increase above 600 K.Under non-magnetic excitation,the ellipsometry parameter of Co thin film is slightly shifted down within 300K?400K,while above 400 K is shifted up with the increase of temperature.(4)The ellipsometry measurement experiment of Ni and Co films under the temperature change of 300K?900K after magnetization was preliminarily carried out to illustrate the influence of temperature on the optical properties of ferromagnetic Ni and Co films,laying a foundation for the future research on the temperature response of optical properties of magnetic materials under the action of magnetic field.