Optical and magneto-optical spectra of magnetic granular alloys

We present the results of the experimental and theoretical investigation of the optical and magneto-optical (MO) spectra of magnetic granular films (Co70Fe30)xAg1−x, CoxAg1−x, in the energy range 0.5-4.0 eV of incident light. The MO properties were investigated in the geometry of transverse Kerr effect. The MO spectra of granular alloys are quite different from the spectra of homogeneous films. The amplitude of Kerr signal and the MO spectra profile depend on the granular and matrix material, the concentration and the shape of the grains and the annealing temperature. We interpret the obtained spectra in the framework of the effective medium approximation that allows to make some conclusions about ferromagnetic particle concentration and their shape.