Calculating Curie temperatures for rare-earth permanent magnets: Ab initio inspection of localized magnetic moments in d-electron ferromagnetism

摘要

We present a data set of calculated Curie temperatures for the main-phase compounds of rare-earth permanent magnets. We employ ab initio electronic structure calculations for itinerant ferromagnetism and an effective spin model for finite-temperature magnetism. Curie temperatures are derived on the basis of a classical Heisenberg model mapped via Liechtenstein's formula for atomic pairwise exchange couplings. Relative trends with respect to the species of rare-earth elements in calculated Curie temperatures for R2Fe14B are in agreement with experimental trends. A quantitative comparison between calculation and experimental data found in the literature points to an effective range of exchange couplings imposing a limit on the validity range of the effective spin model.