Optical and magneto-optical study of Fe/Si multilayers

Experimental and theoretical investigations of the optical and magneto-optical (MO) properties of sputter deposited Fe/SixFe1-x multilayers (MLS) are presented. The diagonal and off-diagonal components of the optical conductivity tensor of the MLS have been determined in the photon energy range 0.8-5.8 eV from the measurements of the magneto-optical complex Kerr angles and the optical data measured by the spectroscopic ellipsometry and compared with the theoretical ones calculated from first principles in density functional theory by the LMTO method within the supercell approach. The calculations have been performed for different models of iron silicide structures. In particular, various spacer layer structures: metallic FeSi and semiconducting FeSi2 iron-silicide phases, as well as pure Si and Fe were investigated. The comparison of the recorded and calculated spectra confirm the conclusion inferred from other studies that the spacer layer structures represent semiconducting epsilon-FeSi and beta-FeSi2 phases rather than the metallic FeSi phase.