Magnetic properties in amorphous Fe100-XErX films

Amorphous Fe100-xErx films, with 8<X<30 were prepared by RF sputtering and their magnetic properties studied. The saturation magnetization M-o, the un iaxial anisotropy constant K-u and the coercive field H-o were studied as a function of the Er composition. The Er moment at 4.2 K found to be about 7 mu(B) revealed a "sperimagnetic" structure for the Er. The mean field theo ry has been used to explain the temperature and compositional dependencies of the magnetization of Fe100-xErx. This analysis yields the effective exch ange interaction between Fe-Fe and Fe-Er atom pairs. K-u and H-c are relate d by the equation Hc=alpha K(u)n/mu(o)M(s) with the fitting parameters a an d n. (C) 2000 Elsevier Science S.A. All rights reserved.