Bifurcation of magnetic anisotropy caused by small addition of Sm in (Nd1−xSmxDy)(FeCo)B magnetic alloy

Abstract

In sintered (Nd1−xSmxDy)(FeCo)B magnets, the contributions of “soft” (Nd1−xSmxDy)2(FeCo)2B and “hard” (Nd1−xSmxDy)2(FeCo)14B phases to the temperature and field dependences of magnetization have been distinguished. The increase in Sm concentration up to 3% provides stronger interlattice RE-TM (RE—rare-earth metals, TM—transition metals) exchange interaction. Contributions of the NdDy and Sm to magnetic anisotropy have been determined. The competition between the positive contribution of Nd and Dy and the negative contribution of Sm ions results in non-monotonous temperature and Sm concentration dependencies of anisotropy field. Anisotropy of the studied alloys is intermediate between “easy axis” and “easy plane” symmetry.