MAGNETO-OPTICAL SPECTRA OF ULTRATHIN Co FILMS SANDWICHED BETWEEN Pt LAYERS

Abstract

Abstract-Magneto-optical Kerr spectra have been measured for Pt(2 nm)/Co(0.2-2 nm)IPt(60 nm) sandwich films, prepared by a molecular beam epitaxy technique onto MgO( Ill) substrates. From the reflection high energy diffraction observations, the Co layers on the Pt( Ill) base layers were confirmed to have a twinned fcc structure. The Kerr rotation of the sandwich films increased with increasing photon energy in a si milar manner to those of Pt-Co alloys and multilayers, and as the Co layers become thicker, the magnitude of Kerr rotation becomes larger throughout the range of measurement (0.8-4:1 eV). In order to characterize the magneto-optical properties of pt/Co interfaces, the (00";; spectrum of a Pt monolayer was estimated from the (00";; of the sandwich by assuming that the Pt monolayer neighboring the Co layer are spinpolarized. The CiX1:; for the Pt monolayer are considerably larger in magnitude than those of thick Co and Pt-Co sputtered alloy films in the high energy region. The experimental Kerr spectra with various Co thicknesses were reproduced by the simulation using (00";; for the spin-polarized Pt.