Noncubic Garnet Anisotropy from Growth-Induced Pair Ordering

Abstract

A growth-induced pair anisotropy model is presented to account for the pronounced noncubic anisotropies recently studied in flux-grown magnetic garnets. In this model the noncubic anisotropy arises from the presence of a relatively small amount of growth-induced short-range pair ordering. The resulting pair anisotropy consisting in general of both dipolar and pseudodipolar terms is shown to have many of the features of the observed anisotropy. In particular we perform a detailed calculation of the anisotropy energy under the {110} and {112} growth facets of the garnets when such short-range pair ordering occurs between ions of the rare-earth sublattice and those of the iron sublattices. Good agreement is obtained with presently available experimental data.