Direct evidence of magneto-optical and optical size effects in Fe-Ag granular films

For prepared FexAg100-x granular films, the Kerr rotation and ellipticity change monotonically with the photon energy and after annealing have two peaks near 2.0 and 3.8 eV, respectively. The peak value increases with annealing temperature T-A. Numerical calculations show that the peak at low energy is induced by the change in the off-diagonal element of dielectric tensor of Fe particles and the peak at high energy results from the changes in optical properties of Ag particles near its plasma absorption edge. These results clearly show the simultaneous existence of both the magneto-optical size effect of Fe particles and optical size effects of Ag particles in metallic granular films.