MAGNETOOPTICAL SPECTRA OF ULTRATHIN AU M/CO/AU FILMS (M=AU, CU, AG)/

Complex polar Kerr and Faraday effects between 1.5 and 5.2 eV in ultra thin Au/M/Co/Au films, with M = Au, Ag or Cu, prepared by thermal evap oration under ultra high vacuum condition are reported. The structure in the dispersion spectra is dominated by the effect of the Au layer u nderneath the ultrathin Co film. Thanks to the high layer perfection a nd step-like interface profiles strong sharp peaks in Kerr rotation, c entered at the Au plasma edge near 2.5 eV, are observed. The introduct ion of Ag or Cu overlayers, which also display plasma edge effects in the considered energy range, modifies the spectra. This behaviour is s atisfactorily explained by the electromagnetic wave model in magnetic multilayers.