Magneto-Optical Spectra in Ni/Ag Superlattices.

Abstract

We investigated the Kerr rotation and ellipticity spectra in Ni/Ag superlattices. Samples were prepared by magnetron sputtering on glass substrates. The Kerr rotation and ellipticity were measured in the photon energy range of 1.25-4.5 eV at room temperature. All samples showed a negative peak of ellipticity near 4.0 eV. This peak is caused by the effect of both Ni layers, reflecting their bulk property and the absorption edge of Ag. In addition, the Kerr rotation of each sample showed a small negative peak in the range of 3.0-3.6 eV. The peak shifted to a higher energy level with increasing Ag layer thickness, while it was independent of the thickness of Ni layers. These results suggest that electronic state of the Ni or Ag layers is different from the bulk one.