Amorphous rare-earth alloys: random-anisotropy antiferromagnetism

The model of randomly oriented single-ion uniaxial anisotropy field is extended to the case of antiferromagnetic exchange interaction between rare-earth ions. A self-consistent two-spin cluster approximation is used to calculate the magnetization curves for a model system of spin 1. The results are in good qualitative agreement with experimental data on amorphous REsub(x)Cusub(1-x) and REsub(x)Agsub(1-x) alloys (RE = Tb, Dy, Ho). In particular, the observed increase of the 'coercive' field with increasing x in REsub(x)Cusub(1-x) alloys is accounted for. (author)