Using first-principles calculations, we investigate the positional dependence of trace elements such as O and Cu on the crystal field parameter A20, proportional to the magnetic anisotropy constant Ku of Nd ions placed at the surface of Nd2Fe14B grains. The results suggest the possibility that the A20 parameter of Nd ions at the (001) surface of Nd2Fe14B grains exhibits a negative value when the O or Cu atom is located near the surface, closer than its equilibrium position. At the (110) surface, however, O atoms located at the equilibrium position provide a negative A20, while for Cu additions A20 remains positive regardless of Cu's position. Thus, Cu atoms are expected to maintain a positive local Ku of surface Nd ions more frequently than O atoms when they approach the grain surfaces in the Nd-Fe-B grains.
ASJC Scopus subject areas
- Physics and Astronomy(all)