Magnetic coupling between rare-earth and iron atoms in the La1−xRxFe11.5Si1.5 (R=Ce, Pr, and Nd) intermetallics

A systematic investigation on the effect of R doping, particularly the magnetic coupling between R and Fe, has been performed for the La1−xRxFe11.5Si1.5 intermetallics (R=Ce, Pr, and Nd). A magnetic interaction comparable to that between Fe atoms is found between the R and Fe atoms, which causes an enhancement of the Curie temperature up to ∼11% when ∼30% of the La atoms are replaced by R. The R–Fe coupling is further found to be strongly dependent of the species of the rare earths. It monotonically grows as R sweeps from Ce to Nd. This could be a consequence of the lanthanide contraction, which causes an enhancement of the intra-atomic magnetic coupling.