Enhancement of anisotropy in Nd2Fe14B driven by Eu substitution -: art. no. 014415

The Eu substitution for Nd in Nd2Fe14B leads to the decrease of the magnetization of the system. This reduction is in agreement with the dilution of the Nd sublattice magnetization by a nonmagnetic ion. However, contrary to the behavior found for the substitution of Nd by nonmagnetic species, no decrease of the magnetocrystalline anisotropy is found upon Eu substitution. Indeed, the strength of the anisotropy field at room temperature is enhanced in the Eu substituted compounds. We determined by x-ray-absorption spectroscopy at the Eu L-3-edge that the electronic state of the Eu ion in the metallic Nd2Fe14B host is trivalent. Our results suggest the role of a non-negligible orbital contribution of Eu ions that can be explained by taking into account the mixing of the lowest spin-orbit multiplets of Eu3+.