Electronic and magneto-optical properties of ion beam sputtered rare earth-FeCo thin films

Abstract

Amorphous rare-earth-transition-metal thin films have been deposited in ultrahigh vacuum by ion beam sputtering. Film composition and purity are controlled by Auger electron spectroscopy and X-ray photoemission spectroscopy. X-ray and ultraviolet photoemission valence band spectra are compared with polar magnetooptical Kerr-effect spectra in the photon energy range 0.5<or=hv<or=5 eV. The f to d transitions are found to enhance magnetooptical effects considerably in NdCo and NdFeCo films, while GdFeCo and TbFeCo spectra are dominated by d excitations of the FeCo. Evidence is found for the coexistence of Yb/sup 2+/ and Yb/sup 3+/ valence state in amorphous YbFeCo and possible f to d contributions in the magnetooptical spectrum.<<ETX>>