Magnetic Ordering Properties of Rare-Earth Ions in Strong Cubic Crystal Fields

摘要: A theoretical discussion of some the effects resulting from interplay between strong crystalline-field torques and weaker exchange acting on rare-earth ions is given. The crystalline field supposed to have cubic symmetry. semiclassical effect in determining easy directions, anisotropy, depression ground-state ordered moment values for series given used interpret results exact calculations. It shown that rare earths may be so large no long-range magnetic order possible at low temperatures. theory applied case phosphides. Adjusting parameters yield observed (and directions) TbP ErP, one predicts HoP agreement with experimental value, TmP will not all. "holmium flopside" pattern explained as being due dipole forces. ratio sixth-order component potential fourth-order must increased five times over naively computed value reach experiment; however, an indication a possibly important noncubic change this appreciably.