Magnetization-induced second harmonic generation in ultrathin Au/Co/Au films

Ultrathin magnetic cobalt-based Au/Co/Au trilayers have been studied by the optical second harmonic generation (SHG) and by the linear magneto-optical Kerr effect (MOKE). We show that SHG has a selective interface and surface sensitivity, whereas MOKE is bulk-sensitive. SHG was used to probe the surface plasmon resonance in Au/Co/Au films. The resonant coupling of surface plasmons with SHG, results in an enhancement and sign reversal of nonlinear magneto-optical effects. Model calculations of the observed phenomena are given on the basis of a nonlocal field theory, which permits to distinguish the different interface contributions to SHG.