Magneto-optic properties of thin EuS/Co and EuS/Cu films on Si(111) substrates

Thin EuS films of 5.5 and 11 nm have been grown at 300 K on epitaxial Co(111) and Cu(111) surfaces on Si(111) substrates. The EuS layers show volumetric reflections in the RHEED pattern indicating that the EuS is deposited in form of small crystallites on the Co or Cu surface. The magneto-optic properties are investigated by polar Kerr spectroscopy at 300 K and 10 K. At 10 K, a clear signature of the intra-Eu 4f-5d transition is observed at 1.8 eV and at 4.2 eV. Below 1 eV, the magneto-optic contribution of the Co layer is dominant. The influence of the Co or Cu layer on the magnetic ordering of the EuS layer is studied by measuring the Kerr spectra as a function of temperature. The layered structures exhibit an in-plane magnetic anisotropy. Estimates of the paramagnetic EuS contribution to the spectrum at 300 K suggest only a weak coupling between the EuS film and the Co layer. (C) 2002 American Institute of Physics.