The Magneto-Optical Kerr Effect Enhancement in CoxAg1?x Granular Films

The magneto-optical Kerr effect enhancement in CoxAg1—x granular magnetic films annealed at 100, 250, 400, 500 °C was studied. The optical constants, the complex dielectric function and magneto-optical Kerr parameters were measured at room temperature. For the sample Co2Ag98, strong Kerr effect enhancement is observed around the Ag plasma edge. With increasing annealing temperature, the values of the Kerr rotation θK and Kerr ellipticity εK increase, resonance-like peaks appear in the Kerr rotation, and the peak positions are shifted toward the low photon energy region. As the Co composition x increases the Kerr effect enhancement is weakened and disappears for x < 50%. From the analysis of the experimental data, it is concluded that the magneto-optical Kerr effect enhancement is due to the presence of the steep plasma edge.