Local-anisotropy and spin-nature effects in ferrimagnetic Ising chains: New compensation phenomena

Abstract

We propose a general treatment for solving ferrimagnetic chains, made up of two spin sublattices (s,S), by assuming a Z-Z exchange coupling between nearest neighbors. Exact expressions of the susceptibility will be derived for s=(1/2) spins alternating either with classical moments or with arbitrary S quantum spins. In the first case, the dimensionality of the space available to classical spins will be taken into account for describing the magnetic behavior. New specific effects will be discussed when the sublattice magnetizations nearly or exactly compensate one another. In particular, the occurrence of a compensation temperature, corresponding to exact cancellation of the opposite magnetizations, as in three-dimensional ferrimagnets, will be revealed. This manifestation will be shown to depend drastically on the spin multiplicities and on the ratio between magnetic moments 2GS/g.