THEORY OF NONLINEAR MAGNETOOPTICS

Nonlinear magneto-optics is a very sensitive fingerprint of the electr onic, magnetic, and atomic structure of surfaces, interfaces, and thin ferromagnetic films. Analyzing theoretically the nonlinear magneto-op tical Kerr effect for thin films of Fe(001) and at Fe surfaces we demo nstrate exemplarily how various electronic material properties of ferr omagnets, such as the d-bandwidth, the magnetization, the substrate la ttice constant, and the film-thickness dependence can be extracted fro m the calculated nonlinear Kerr spectra. Furthermore, we show how the substrate d electrons [Cu(001)] affect the nonlinear Kerr spectra even without being themselves spin-polarized and without film-substrate hy bridization. We show that the Kerr rotation angle in second-harmonic g eneration is enhanced by one to two orders of magnitude compared to th e linear Kerr angle and how symmetry can be used to obtain the directi on of magnetization in thin films and at buried interfaces from nonlin ear magneto-optics. (C) 1996 American Institute of Physics.