Abstract
The large part of the ferromagnetic anisotropy of attributed to the presence of is explained, for small , by means of a one-ion model. The residual orbital angular momentum of is constrained by the crystal electric field to lie parallel to the axis of trigonal symmetry. Spin-orbit energy couples the spin to this axis, accounting for the anisotropy energy. By fitting the theory to cubic anisotropy data one finds . The assumption that cations are mobile at higher temperatures leads to a quantitative explanation of the annealing-induced anisotropy energy. The mean orbital magnetic moment of is predicted to be large ( Bohr magneton) and anisotropic ( Bohr magneton) at low temperatures.
- Received 24 February 1958
DOI:https://doi.org/10.1103/PhysRev.110.1341
©1958 American Physical Society