2001 Fiscal Year Final Research Report Summary
Crystal Orientation of Anisotropic Fe-Pt Permanent Magnet
| Project/Area Number |
11450265
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | The Research Institute for Electric and Magnetic Materials(RIEMM) |
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Principal Investigator |
WATANABE Masato The Research Institute for Electric and Magnetic Materials, Thin film Materials Gr, Senior Researcher, 付置研究所・薄膜材料グループ, 主任研究員 (40249975)
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| Co-Investigator(Kenkyū-buntansha) |
NIWA Eiji The Research Institute for Electric and Magnetic Materials,Functional Materials Gr,Researcher, 付置研究所・機能材料グループ, 研究員 (40201694)
NAKAYAMA Takahumi The Research Institute for Electric and Magnetic Materials,Functional Materials Gr,Senior Researcher, 付置研究所・機能材料グループ, 主任研究員 (40164363)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Fe-Pt permanent magnet alloy / Ordered phase alloy / Single crvstal / Maximum energy product / Solution growth |
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| Research Abstract |
The head investigator in this project and his collaborates succeeded in fabricating c-axis oriented Fe-Pt based alloy thin films with the energy product exceeding 35 MG-Oe, which is the highest value as thin film magnets. Thus, apparent improvement of magnetic properties in bulk Fe-Pt alloys is expected by controlling their crystal orientation. In this project, we laid a research plan of investigating crystal orientation dependence of magnetic properties in Fe-Pt single crystals. This plan aims at adapting to shape multiplicity of permanent magnets and at optimizing magnetic properties of this alloy. Single crystal preparation of Fe-Pt alloy has been reported to be difficult, due to the formation of twin microstructures to release stress of order-disorder transformation. First, we prepared Fe-37at%Pt single crystals and investigated orientation dependence of magnetic properties in the sample aged at 640℃. In the case of the sample aged for 45 hours, showing the maximum coercivity, apparent difference of coercivity could not be observed between the directions of magnetization easy axis [001] and hard axis [100]. However, we could confirm a difference of coercivity by a factor of 2 in the over-aged sample (for 280 hours). On addition to the 37 at%Pt composition, fabrication of Fe- 39.5 at%Pt- 0.75 at%Nb single crystal was attempted by precise casting method using a molding material with low heat conductivity, resulted in a single crystal grain with the size of 2mm length. Solution growth of Fe-Pt single crystal was also attempted using Fe-Pt-B pseudo binary alloys as solvent.
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