Theory of Brillouin cross section for scattering from magnetic multilayers: Second-order magneto-optic effect in Ni/Cu bilayers and trilayers

The Brillouin light scattering technique has been exploited to detect spin waves in Ni/Cu bilayers and trilayers deposited by RF sputtering. In order to reproduce the experimental results, a macroscopic partial waves approach is used for the calculation of the normal modes, allowing the application of this model to magnetic multilayered structures. The Brillouin cross section of the multilayer is calculated with the Green's functions method, taking into account both first and second order magneto-optic effects ~Faraday and Voigt effect, respectively!. By measuring Brillouin spectra for different applied fields we have determined the magnetic parameters of the films as well as the ratio between the first and second order magneto-optic constants.