THEORY FOR THE NONLINEAR MAGNETOOPTICAL KERR-EFFECT AT FERROMAGNETIC TRANSITION-METAL SURFACES

We present a theory for the nonlinear magneto-optical Kerr spectrum of Fe by extending our previous analysis. The obtained results are compa red with recent experimental data for a Fe(110) surface. The various g eneral features of the nonlinear Kerr effect, the detailed dependence of the Kerr spectrum on exchange interaction, and Fermi-level crossing on frequency and spin-orbit interaction are discussed. In particular, we demonstrate how the spectrum depends on d-band width and sd hybrid ization. Thus, we are able to extract band narrowing due to electronic correlations or due to a reduced coordination number from the spectra . The latter is particularly relevant for thin films. To shed further light on the dependence of the nonlinear Kerr spectrum on electronic p arameters we also calculate the linear magneto-optical Kerr effect. Th e differences between the Kerr spectra of Fe and Ni are discussed.