Magnetism in the Itinerant Electron Model

1 8.1 Generalities

We have seen in chapter 3 that many elements, in the free atom state, possess a magnetic moment (tab. 3.1). However, in the solid state, the majority of them are diamagnetic: only the metals of the third row, from chromium to nickel, and most of the rare earth elements and actinides carry magnetic moments (tab. 3.2). This means that the formation of a chemical bond significantly alters the electronic orbits that are responsible for magnetism. The transition metals (3d series) are in fact far more sensitive to these effects, and the magnetic moments observed in these elements, their compounds, and alloys, generally differ markedly from those of the free atoms or isolated ions. We have already treated, in the preceding chapter, the materials in which the electrons responsible for the magnetism are localized. In other situations, most importantly in the metals and alloys of the 3d transition series, the magnetic moment carried by a magnetic atom is...