Transition metal alloys

Abstract

A particular interest in the properties of transition metal alloys at the present time is the problem of the occurrence of localised electron spins. There is also, particularly in the first period, the problem of ordered magnetic states. Recent work has established that suppression of localised spin may occur in materials with a high density of states at the Fermi level, through the agency of combining those conduction states (with their balanced spin occupation) with the local state favoured by the impurity atom. The density of states, however, is not a sufficient discriminating parameter, and additional properties, such as the high susceptibility of e.g. Pd, play an important role in stabilising magnetic atomic states. Ferromagnetism on the band model is favoured by a high density of states, originating from the d-band. A high density of conduction states, however, suppresses spin moment on impurity atom, by broadening the d-states considerably and favouring equal spin occupation. Very particular interest, therefore, attaches to the properties of alloys at concentrations where ferromagnetic behaviour begins, such as vanadium-iron between 15 % and 25 % Fe