Variable angle of incidence analysis of magneto-optic multilayers

Abstract

We have applied the technique of variable angle of incidence spectroscopic ellipsometry (VASE) to the analysis of multilayered magneto-optic structures. With this instrument we measure the complete pseudodielectric tensor (diagonal and off-diagonal elements) for the sample of interest at variable angles of incidence. We have also developed computer software to perform a best-fit analysis of the measured data, providing optical constants, Voigt parameters, and layer thicknesses for the individual layers in the sample. Additionally, given an estimate of the material parameters, this software will provide an estimate of the optimum spectral range and angles of incidence for accurate characterization of the sample. An example of the above is given for a series of thicknesses of Dy/Co compositionally modulated multilayers deposited on a thick silver layer and subsequently overcoated with a thick layer of SiO. Results confirm the predicted optimum range of accuracy for this material system and effectively delineate the useful spectral range of this technique.