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First-principles study of chemical substitution effects in NdFe12 and NdFe12N

NIMS学術シンポジウム「磁性材料イノベーション」, 東京国際フォーラム

2018年10月15日(月)

Yosuke Harashima (AIST), Taro Fukazawa (AIST) and Takashi Miyake (AIST, NIMS)

Abstract

 Experimental reports on NdFe12N and Sm(Fe,Co)12 films have attracted renewed interest in RFe12-type compounds as a potential main phase of a new permanent magnet. One issue is search for a substitutional element which stabilizes the ThMn12 structure with keeping good magnetic properties. In the present work, we theoretically study the effects of chemical substitution on the structural stability and magnetic properties of NdFe12(N) based on density functional theory. Main conclusions are the followings. (I) The calculation of NdFe11M (M=Ti, V, Cr, Mn, Co, Ni, Cu, Zn) [1] shows that M=Co has positive effect on stabilization, with keeping high magnetization. (II) Chromium substitution at Fe site raises the Curie temperature at low Cr concentrations [2]. (III) The formation energy of RFe12 (R=rare earth) relative to R2Fe17 and bcc-Fe has strong correlation with the size of R, and takes a minimum for R=Dy [3]. (IV) The magnetization is suppressed when N in NdFe12N is replaced with B and C [4], while the magnetic exchange coupling between the Nd and Fe(8j) sites is enhanced by the replacement [5].
[1] Y. Harashima et al., J. Appl. Phys. 120, 203904 (2016). [2] T. Fukazawa et al., J. Phys. Soc. Jpn.87, 044706 (2018). [3] Y. Harashima et al.,arXiv:1805.12241. [4] Y. Harashima et al., Phys. Rev. B 92, 184426 (2015). [5] T. Fukazawa et al., J. Appl. Phys. 122, 053901 (2017).



その他特記事項

 CDMSI, MI^2I


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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