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 compared with recent experimental data for a Fe(110) surface. The various general 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 hybridization. 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 parameters we also calculate the linear magneto-optical Kerr effect. The differences between the Kerr spectra of Fe and Ni are discussed.