On the Magnetic Properties of Cubic Cerium

Abstract

Since the mass separation of . rare earth metals has become possible by means of the ion exchange technique/> the magnetic properties of these metals have been extensively studied experimentally. It is now known that many of these elements are ferroor antiferromagnetic and their magnetic behaviors are quite different from those of the iron group. The carriers of the magnetic moment in rare earth metals are the electrons occupying 4 f orbitals incompletely, which seem to localize almost as if they were in the free atomic state, and hence keep their orbital magnetic moments without much interference from the electric crystalline field. The mechanism of exchange coupling between magnetic· moments in rare earth metals is therefore expected to be somewhat different from the case of ordinary magnetic metals in that conduction electrons would . play an important role in aligning the spin magnetic moments of the ion core, each of which is strongly coupled to the orbital moment through the spin-orbit interaction. This is Zener's picture of exchange. 2> A similar idea was applied by Pauling3> to Gd and more recently investigated in detail by Kasuya4> in connection with the electric and magnetic properties of transition metals. As was pointed out by Kasuya,5> the strange feature of magnetism in rare earth metals is believed to come from the fact that, beside the extraordinary exchange mechanism mentioned above, there .. exist interactions between an orbital moment and crystalline field or between an orbital moment and other orbital moments, which will give rise to complicated effects, varying with the number of 4 f electrons and with the temperature. The object of this paper is to present an atomistic theory of the thermal and magnetic properties of metallic cerium. This element is the simplest one in the sense