R-T and R-R exchange interactions in the rare-earth (R)-transition-metal (T) intermetallics : an evaluation from relativistic atomic calculations

摘要: Intra-atomic exchange integrals J4f-5d, J4f-6s and J4f-6p for rare-earth trivalent ions were obtained from relativistic self-consistent field atomic calculations, using the local-density approximation correlation potential. The effective (molecular-field) coefficients nRT between transition-metal nRR based on a simplified three-sublattice (4f, 3d conduction electron) mean-field model. Quantitative results show decrease in magnitude of across series, which agrees well with values observed many rare-earth-transition-metal intermetallic series. It is shown that 4f-5d interaction far more important than 4f-6s 4f-p interactions, as expected Campbell model interactions occurring intermetallics.