First-Principles Calculation of Nonlinear Surface Magneto-Optical Response of a Ferromagnetic Multilayer

Abstract

First-principles calculations, based on the full-potential linearized augmented plane wave (FLAPW) method, including spin-orbit coupling (SOC) as second variational treatment within a self-consistent procedure, were carried out to obtain the nonlinear optical (NLO) response from the fcc multilayer structure ½Nið1 MLÞ=Cuð1 MLÞ 2 ; grown on Cu(001). Within the framework of a supercell approach we obtain the wave functions and the bandstructure for further calculation of the spectra of the nonlinear optical susceptibility tensor ð2Þ i jk : The reflected electric field at the frequency of the second harmonic (SHG) 2! is calculated on the basis of the surface-sheet model and the resulting SHG intensities, azimuthal dependence for main experimental geometries and Kerr angles are presented for the cases of the in-plane and out-of-plane magnetization of the multilayer, which correspond to longitudinal and polar magneto-optical configurations (MOC) respectively. We compare current results with previously obtained ones for the single fcc Ni/Cu(001) bilayer. It is shown, that in the case of the out-of-plane magnetization the magnetic tensor elements of the ð2Þ i jk tensor are smaller than the nonmagnetic ones by only one order of magnitude. In the case of in-plane magnetization the magnetically induced components of ð2Þ i jk become even comparable in magnitude with the nonmagnetic ones, confirming the important role of magnetic properties in the NLO response.