Magnetic Anisotropy Around Grain-Boundaries in Rare-Earth Magnets and Their Coercivity

Abstract

Recently, several experimental studies for sintered Nd-Fe-B magnets have shown that their coercivity can be decisively affected by atomic structures around the grain boundaries in the magnets. In this article, a theoretical review is given on possible coercivity reduction mechanisms in sintered Nd-Fe-B or rare-earth based permanent magnets by focusing on the anomalous local magnetic anisotropy found for Nd ions on interfacial structures, based on first-principles calculations and an effective spin model. [doi:10.2320/jinstmet.JA201604]