A phase diagram for amorphous magnetic alloys

We have constructed a phase diagram for the magnetic behaviour of an amorphous metallic alloy using ideas suggested by recent work of Sherrington and Southern. We propose that a spin‐glass state may be stabilized by the presence of a local anisotropy field of random orientation and constant magnitude, D, rather than by fluctuations of the exchange constant J. Calculations have been performed for S=1 and the classical case of S→∞ with several values of D, and over a wide range of temperature. The magnetization curves show the existence of a well‐defined spin‐glass transition of a well‐defined spin‐glass transition temperature and a sizeable coercive field, which are both functions of D. The results are shown to be in qualitative agreement with experiments on amorphous REFe2 ferromagnetic alloys.