Magnetic Properties of Amorphous Fe100-xGdx (18⩽X⩽70) Alloys

The magnetic properties of amorphous Fe100-XGdx (18⩽X⩽70) alloys were prepared by melt-quenching, and were analyzed using molecular field theory employing a two-sublattice model. The spin structure was that of simple ferrimagnetic ordering, and the moment of Fe is about 2μB over a wide concentration range, conspicuously in contrast with that of amorphous thin film. Curie temperatures were higher than those for thin films by about 60 to 100°. The temperature dependence of the magnetization can be fitted to the molecular field theory curve with three exchange constants as the fitting parameters. The results for the concentration dependence of the exchange parameters are discussed in comparison with the case for thin films.