Study on magneto-optical and magnetic properties using a magneto-optical and ellipsometric spectrometer

Abstract

Recently, numerous important studies have been made in the field of magnetism with the current vacuum technologies and there has been a renaissance in magnetism. One of the most important field in magnetism is magneto-optical Kerr effects(MOKE). It has been attracting much attention due to applications of them as a tool in probing magnetism as well as a readout mechanism in high-density digital magneto-optical recording. Therefore, studying MOKE is very useful to understand the magnetic properties of novel magnetic materials and to implement the magneto-optical recording. In this study, we have designed and fabricated the magneto-optical and ellipsometric spectrometer, which was essential to study magneto-optical and magnetic properties. We have combined two equipments, magneto-optic Kerr spectrometer and spectroscopic ellipsometer, into one system. Therefore, the abilities of the system were divided by two parts ;the part for the measurement of magneto-optical Kerr rotation angle and ellipticity, and the other part for determination of the complex refractive index of a sample. Since the system was adopting a photoelastic modulator(PEM), we have studied the effects of the imperfect polarizer and analyzer in the phase-modulated magneto-optical Kerr spectrometer and spectroscopic ellipsometer using Jones matrices to represent the imperfection of the polarizer and analyzer. We have found that the polarizer and analyzer imperfections in the magneto-optical Kerr spectrometer were eliminated within the first-order approximation, because of the applied magnetic field independence. Furthermore, the polarizer and analyzer imperfections and the incorrect setting of the amplitude of the phase-modulation in the spectroscopic ellipsometer were also canceled within the first-order approximation by zone average. We have found some new measurement methods for MOKE. First of them is to determine the off-diagonal element of the dielectric tensor, without measuring the ellipti...