Effect of lattice relaxation on magnetic anisotropy:Zr-dopedSm2Co17

The magnetic anisotropy energy (MAE) in rare-earth/transition-metal hard magnets originates from the onsite anisotropy of the rare-earth element with additional contribution from the transition-metal sublattice. While SmCo 5 can be transformed to Sm 2 Co 1 7 by partial substitution of Sm by Co 2 dumbbells, the MAE in Sm 2 Co 1 7 is noticeably smaller compared to that in SmCo 5 . However, small dopings of nonmagnetic Zr significantly increase the MAE in Sm 2 Co 1 7 . We show that the changes to the MAE in Sm 2 Co 1 7 can be traced down to the reduction of the crystal field at the Sm site due to the Co sublattice relaxation upon Sm-Co 2 substitution which is subsequently restored upon substitution of Co 2 → Zr.