MAGNETISM OF AMORPHOUS TRANSITION-METALS AND ALLOYS

Recent development in the magnetism of amorphous transition metals (TM s) and alloys is summarized from the theoretical point of view. The ma gnetism is shown to be characterized by the itinerant-electron spin gl ass and re-entrant spin-glass behaviors around amorphous Fe, the enhan cement of Curie temperature around amorphous Co, and a weak ferromagne tism around amorphous Ni. The systematic change in magnetism is explai ned by the main-peak position in the densities of states. The non-line ar magnetic couplings and the local environment effects on the local m oments are the origin of the itinerant-electron spin glass. Discussion s are also given of the magnetism of TM-metalloid amorphous alloys and early TM-TM amorphous alloys. In the former, the hybridization betwee n the metalloid p and TM d orbitals determines their simple magnetism, while in the latter the atomic-size effects play an important role in the concentrated region. The degree of structural and configurational disorder is emphasized as a key factor controlling magnetism in vario us amorphous alloys.