Magnetic coupling in amorphous Fe100-xErx films

Temperature and compositional dependences of magnetization of Fe100-xErx sp uttered films (with 8<X<30) are analysed using the mean field theory, and t he sublattice magnetic moments M-Fe and M-Er are calculated as a function o f composition. This analysis yields the effective exchange interaction betw een Fe-Fe and Ee-Er atom pairs. High-field magnetization studies performed at 4.2 K in magnetic fields up to 5.5 T on amorphous Fe100-xErx alloys have revealed, for samples with stoichiometry close to that of a compensated fe rrimagnet, a magnetic behavior that is characteristic of a non-collinear ma gnetic structure of the Er and Fe sublattices. From the non-collinear regim e the exchange interactions between the Fe and Er magnetic sublattices have been accurately evaluated. (C) 1999 Elsevier Science S.A. All rights reser ved.