A low concentration of substitutional impurities such as Ga or Si in R2Fe17 (R=rare earth) raises its Curie temperature. Self-consistent spin-polarized electronic-structure calculations are performed and exchange parameters (Jij) are derived from first-principles for pure Sm2Fe17 and Sm2Fe16A (A=Ga, Si). The changes in exchange parameters with doping are related to the magnetovolume effect and the lowering of hybridization of the iron atoms. Monte Carlo simulations have been performed using the calculated Jij's to derive the Curie temperature of phases containing Ga and Si impurities. The results are in very good agreement with the experimental data.
ASJC Scopus subject areas
- Physics and Astronomy(all)