Magneto-optic multilayers: Fundamental and technological aspects

We describe our magnetic and magneto-optic (MO) studies on some multilayers based on Ag, Au and Pt, such as Fe/Ag, Fe/Pt, Co-Ni/M (M = Pt, Au) prepared by evaporation under UHV conditions. In Co-Ni/M, the surface anisotropy increases linearly with the addition of Co verifying the single ion model. The Curie temperature can be tailored by the addition of Co without affecting adversely the properties of interest for MO storage applications. For instance. in Fe/Ag, the MO effect shows enhancement due to Ag plasma resonance and in Fe/Pt the effect is due to interaction of Pt. The spectra can be explained by a phenomenological model though quantitative agreement is not obtained. In Au-based multilayers. the MO Kerr spectra show the effect of plasma resonance of Au, particularly for thinner layers. Some of the results could be modelled by electromagnetic model. The Kerr spectra for Co-Ni alloy films could also be modelled with success using effective medium theory which also confirms the absence of any effect from hybridisation between Co and Ni a result which supports our conclusions on the surface anisotropy.