Characterization of magneto-optical recording media

Abstract

This dissertation discusses the optical, magnetic and transport properties of magneto-optical recording media. The various custom-made and off-the-shelf instrumentation used in this study include: a Vibrating Sample Magnetometer (VSM), a modified polarization microscope, a polar Kerr effect loop tracer, a variable angle of incidence ellipsometer, and magnetoresistance/Hall effect/resistivity probes. Most of the samples studied were analyzed for determination of their composition and thickness by Rutherford Back Scattering (RPS) and X-Ray Fluorescence (XRF). The samples investigated were manufactured in several industrial and academic laboratories under different deposition conditions. The optical properties measured include Kerr rotation angle and ellipticity, Fresnel reflectivity coefficients, and calculation of the dielectric tensor. The magnetic properties include measurements of saturation magnetization, coercivity, anisotropy field, calculations of exchange energy parameters, domain wall, and anisotropy energy densities from experimental observations. The transport properties include measurements of magnetoresistance and Hall effect with three different geometries and calculation of the resistivity tensor. The modeling work consisted of modeling the optical path for various instruments, the current distribution in magnetic films, and the calculation of the demagnetizing energy using the fast Fourier transform technique.