Hydrogen dependence of the intrinsic magnetic properties of R2Fe14B

Abstract Magnetization measurements on Dy 2 Fe 14 BH x show that hydrogen increases the magnetization M s , the Curie temperature T c and the magneto-crystalline anisotropy. On saturation, at x = 4.7, M s increased from 9 to 15 μ B per formula unit at 4.2 K, T c increased from 595 to 661 K and the phenomenological fourth-order anisotropy constant K 2 was doubled throughout the range 4.2–300 K. A non-collinear spin structure was deduced for the dysprosium sublattices in the hydride. No spin reorientation was observed for Er 2 Fe 14 BH x . as x was varied at room temperature.