A computational model for rare-earth ferrimagnets and antiferromagnets

A computational model for the calculation of the bulk magnetic properties of rare-earth ferrimagnets and antiferromagnets was developed and justified theoretically in the framework of mean-field theory. To demonstrate its utility, the model was applied to calculate the anisotropic Heisenberg exchange constants of CeTe2 by fitting magnetization curves numerically, and to derive analytical expressions for the spontaneous magnetization as well as the Neél temperature by considering only the crystal-field (CF) ground-state doublet. It turns out that the temperature dependencies of the magnetization and the specific heat calculated with the formulas in absence of an external field are identical with the plots obtained directly with the full lowest CF J-multiplet, manifesting the strong role of the Kramers doublet in the magnetic process at low temperatures. Finally, the model was applied to investigate the effects of the quadrupolar and magneto-elastic (QM) interactions on the magnetic properties of the system.