Growth-Induced Anisotropy by Preferential Site Ordering in Garnet Crystals

The noncubic anisotropy observed under growth faces of certain mixed garnet crystals is explained in terms of the preferential occupation (by one of the two types of rare-earth ions) of particular rare-earth sites. The effect depends on the coordination of the rare-earth ion with its second-nearest tetrahedral iron neighbors. The theory is related to, but different from, the pair-ordering theory of Rosencwaig and Tabor, and the difference is discussed.