Second harmonic generation from magnetic surfaces and thin films

In this paper we discuss the magneto-optical Kerr effect in the frequency doubled light (MSHG, magnetization-induced second harmonic generation) generated at interfaces of ultrathin ferromagnetic films and the surface of crystals having inversion symmetry. We demonstrate that the `magnetic signals' like the nonlinear Kerr angle or the asymmetry can be strongly affected by the `nonmagnetic' part of the second-order nonlinear susceptibility tensor, χ_nonmag⁽²⁾. This changes of χ_nonmag⁽²⁾ can be caused by the change of the electronic structure with film thickness (quantum well states in the Cu cover layer of Cu/Co/Cu(0 0 1)) or by changes of the surface morphology. One monolayer (ML) periodic oscillation during the layer-by-layer growth of Co films on Cu(0 0 1) were observed in the magnetic second order susceptibility χ_nonmag⁽²⁾.