希土類永久磁石の磁化過程解析に向けた磁気特性の第一原理計算

• 土浦 宏紀

  東北大学大学院工学研究科応用物理学専攻 東北大学（CSRN）

• 吉岡 匠哉

  東北大学大学院工学研究科応用物理学専攻 東北大学（CSRN）

• NOVÁK Pavel

  Institute of Physics Academy of Sciences of the Czech Republic

• FISCHBACHER Johann

  Department for Integrated Sensor Systems Danube University Krems

• KOVACS Alexander

  Department for Integrated Sensor Systems Danube University Krems

• SCHREFL Thomas

  Department for Integrated Sensor Systems Danube University Krems

書誌事項

タイトル別名

• First-principles Calculations of Magnetic Properties for Analysis of Magnetization Processes in Rare-earth Permanent Magnets

抄録

It has been empirically known that the coercivity of rare-earth permanent magnets depend on the size and shape of fine particles of the main phase in the system. Also, recent experimental observations have suggested that the atomic scale structures around the grain-boundaries of the fine particles play a crucial role to determine their switching fields. In this article, we review a theoretical attempt to describe the finite temperature magnetic properties and to evaluate the reduction of the switching fields of fine particles of several rare-earth permanent magnet materials based on an atomistic spin model that is constructed using first-principles calculations. It is shown that, over a wide temperature range, the spin model gives a good description of the magnetization curves of rare-earth intermetallic compounds such as R₂Fe₁₄B (R = Dy, Ho, Pr, Nd, Sm) and SmFe₁₂. The atomistic spin model approach is also used to describe the local magnetic anisotropy around the surfaces of the fine particles, and predicts that the rare-earth ions may exhibit planar magnetic anisotropy when they are on the crystalline-structure surfaces of the particles. The dynamical simulation of the atomistic spin model and the corresponding micromagnetic simulation show that the planar surface magnetic anisotropy causes a reduction in the switching field of fine particles by approximately 20-30%, which may be relevant to the atomic scale surface effects found in the experimental studies.

収録刊行物

• 粉体および粉末冶金

  粉体および粉末冶金 69 (Supplement), S118-S125, 2022-01-30

  一般社団法人 粉体粉末冶金協会

キーワード

• rare-earth permanent magnets
• crystal field theory
• first-principles calculations
• atomistic spin model
• micromagnetic simulations

詳細情報

• CRID: 1390572404768315008
• NII論文ID: 130008145813
• DOI: 10.2497/jjspm.69.s118
• ISSN: 18809014
• ISSN: 05328799
• Web Site: https://www.jstage.jst.go.jp/article/jjspm/69/Supplement/69_S118/_pdf
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可