Nonlinear surface magneto-optics of ferromagnetic Ni/Cu(001) from first principles

We present first-principles calculations of the nonlinear optical (NLO) response of a Ni/Cu(001) bilayer. The calculations are based on the full potential linearized augmented plane wave (FLAPW) method with the additional implementation of spin–orbit coupling (SOC). On the basis of this set of eigenstates the magneto-optical transition-matrix elements are evaluated. Using the surface-sheet model the optical reflection properties are determined for the cases of the magnetization vector perpendicular to the surface (polar magneto-optical configuration (MOC)) and for the in-plane magnetization (longitudinal MOC). The nonlinear optical susceptibility tensor elements χ⁽²⁾ _ijk for different magnetization directions as well as the spectral dependence of χ⁽²⁾ _ijk, the resulting intensities, and Kerr angles are presented for the Ni/Cu(001) bilayer. The results show that the magnetic tensor elements of the χ⁽²⁾ _ijk tensor are smaller than the nonmagnetic ones by only one order of magnitude, confirming the important role of magnetic properties in the NLO response. Received: 16 October 2001 / Revised version: 8 March 2002 / Published online: 29 May 2002