EXPERIMENTAL AND THEORETICAL SPIN CONFIGURATIONS IN FE GD MULTILAYERS/

The experimental magnetic phase diagram for three characteristic Fe/Gd multilayered samples is confirmed on a microscopic scale by Fe-57 Mos sbauer spectroscopy using a special geometry. The iron moment rotation in the sample plane at a critical H external field is observed and s ignals the transition from an aligned to a twisted state. This behavio r is accounted for within the framework of an improved mean-field mode l. Self-consistent spin maps are derived for given temperatures and ex ternal fields applied parallel to the sample plane. A unique set of ex change coupling constants is used to calculate both the mean magnetic properties and the Mossbauer spectroscopy data.