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First-principles study on the magnetic anisotropy around the grain boundaries of Nd-Fe-B magnets

The 4th International Symposium on Advanced Magnetic Materials and Applications (ISAMMA) (Phu Quoc)

2017年12月11日(月)

Yasutomi TATETSU, Shinji TSUNEYUKI, and Yoshihiro GOHDA

Abstract

There are several experimental studies showing that the coercivity of Nd-Fe-B magnets is improved after the Ga addition. In these magnets, the existence of Nd6Fe13Ga with tetragonal structure around the grain boundaries is confirmed, however, the roles of Nd6Fe13Ga in improving the coercivity is still an open question. We calculated K1 of several Nd2Fe14B/ Nd6Fe13Ga grain-boundary-model structures using a computational code OpenMX. All atomic positions and cell parameters were optimized. After the structural optimization, we can see that atomic positions of the inner region of Nd2Fe14B and Nd6Fe13Ga are barely changed after the structural optimization. On the other hand, the interfaces have complicated structures. We also find that the K1 recovery of Nd at the interface of the main phase in the Nd2Fe14B/Nd6Fe13Ga systems is better than that of Cu-doped Nd-Fe-B grain boundary model systems that we calculated in the previous study. By analyzing the spin densities of Nd at the interface, we conclude that Nd 5d-electron distribution stretches to the longitudinal direction due to Nd6Fe13Ga, which leads to increasing K1 of Nd.


研究活動

文部科学省

文部科学省
元素戦略プロジェクト(活動紹介)
NIMS磁石パートナーシップ

元素戦略拠点

触媒・電池元素戦略拠点
触媒・電池元素戦略研究拠点 (京都大学)
東工大元素戦略拠点
東工大元素戦略拠点 (東京工業大学)
構造材料元素戦略研究拠点
構造材料元素戦略研究拠点 (京都大学)
高効率モーター用磁性材料技術研究組合
高効率モーター用 磁性材料技術研究組合