Solid-solution stability and preferential site-occupancy in (R-R′){sub 2}Fe{sub 14}B compounds
- CNRS, Inst NEEL, F-38000 Grenoble (France)
- Advanced Material Engineering Div., Toyota Motor Corporation, Susono 410-1193 (Japan)
- Institut Laue-Langevin, CS 20156-38042 Grenoble cedex 9 (France)
The rare-earth (R) uniaxial anisotropy of R{sub 2}Fe{sub 14}B compounds with magnetic R atoms (e.g., Nd or Pr) is at the origin of the exceptional hard magnetic properties achieved in magnets based on these compounds. The uniaxial anisotropy found in Ce{sub 2}Fe{sub 14}B is attributed mainly to the magnetism of Fe. Ce is the most abundant R element and there has been much recent effort to fabricate magnets in which Ce is partially substituted for Nd. In the present neutron study of (R{sub 1−x}Ce{sub x}){sub 2}Fe{sub 14}B (R = La or Nd), Ce is found to enter the R{sub 2}Fe{sub 14}B phase over the entire composition range. The crystallographic parameters decrease with increasing Ce content and the Ce atoms preferentially occupy the smaller 4f sites. It is concluded that Ce in these (RR′){sub 2}Fe{sub 14}B compounds essentially maintains the intermediate valence character found in Ce{sub 2}Fe{sub 14}B. It is proposed that, in this intermediate valence state, Ce weakly contributes to uniaxial anisotropy, thus making a link with the fact that significant coercivity is preserved in Ce-substituted NdFeB magnets.
- OSTI ID:
- 22590796
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 24 Vol. 108; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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