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Magnetic properties of a new family of ternary rare-earth iron nitrides R sub 2 Fe sub 17 N sub 3 minus. delta. (invited)

Journal Article · · Journal of Applied Physics; (USA)
DOI:https://doi.org/10.1063/1.347957· OSTI ID:5562353
; ; ;  [1]
  1. Department of Pure and Applied Physics, Trinity College, Dublin 2, Ireland (IE)
A series of interstitial ternary nitrides R{sub 2}Fe{sub 17}N{sub 3{minus}{delta}} has been prepared via a gas-solid reaction for R=Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y. These nitrides have structures related to the Th{sub 2}Zn{sub 17} or Th{sub 2}Ni{sub 17} structures of the R{sub 2}Fe{sub 17} parent compounds, but the unit cell volumes are 6%--7% greater, and the Curie temperatures are approximately 400 K higher. The Fe-Fe exchange interactions are increased by a factor of 2.8 by nitrogenation, whereas the R-Fe exchange interactions are little changed. All compounds exhibit easy-plane anisotropy at room temperature, except for Sm{sub 2}Fe{sub 17}N{sub 3{minus}{delta}}, which shows strong uniaxial anisotropy and may be used to make permanent magnets. The Er and Tm compounds exhibit spin reorientations below room temperature. The anisotropy due to the iron sublattices is easy plane ({ital K}{sub 1} = {minus}1.3 MJ/m{sup 3} at 4.2 K for Y{sub 2}Fe{sub 17}N{sub 3}), but it changes sign to easy axis with cobalt substitution ({ital K}{sub 1} {approx} 1.0 MJ/m{sup 3} at 4.2 K for Y{sub 2}(Fe{sub 1{minus}{ital x}}Co{sub {ital x}}){sub 17}N{sub 3{minus}{delta}} when {ital x}{ge}0.2).
OSTI ID:
5562353
Journal Information:
Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 69:8; ISSN 0021-8979; ISSN JAPIA
Country of Publication:
United States
Language:
English