MAGNETO-OPTICAL KERR ROTATION SPECTRA IN SPUTTERED GRANULAR Co-Au ALLOY FILMS

Abstract
We prepared Co-Au granular alloy films with compositions ranging from 5 to 38at.% Co on glass substrates by a sputtering method and measured their magneto-resistance and magneto-optical Kerr rotation (ΦK) spectra at RT. As a result, it is found that 20at.% and 28at.%Co-Au films show a large peak at about 3.4eV and small peaks due to the plasma enhancement by the Au matrix at about 2.5eV, respectively. By annealing, the shape of the ΦK spectra became to similar to each other in all the films; namely, two ΦK peaks appear at about 2.0eV and 3.4eV. Thus, ΦK spectra is quite different from those of Co ultra-thin films and bulk Co.