MOSSBAUER STUDIES OF ULTRATHIN FE PT MULTILAYERS/

A series of ultrathin Fe/Pt multilayers, prepared by magnetron sputter ing, were studied by GEMS and transmission MS. The Fe-layer thickness varied from 3 to 12.5 Angstrom and that of Pt from 5 Angstrom to 39 An gstrom. The 3 Angstrom/9 Angstrom Pt sample displays magnetic hyperfin e structure at RT, while the 3 Fe/19 Pt sample is paramagnetic at RT, demonstrating the effect of interlayer interaction. Both samples displ ay out-of-plane magnetic anisotropy with 39 degrees angle with respect to the vertical for the former and nearly 0 degrees angle for the lat ter. The analysis of the spectra of samples with thickness larger than one monolayer of Fe is done with components assigned to individual Fe monolayers. In all these cases a component appears with a hyperfine f ield larger by similar to 10% at RT and 17% at L.He than the correspon ding values of alpha-Fe. This component is attributed to the first mon olayer below the Fe/Pt interface in accordance with similar results in the Fe/Pd system and with theoretical predictions.