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Effect of R-site substitution and the pressure on stability of RFe 12: A first-principles study
We theoretically study the structural stability of RFe 12 with the ThMn 12 structure ( R: rare-earth element, La, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Lu, Y, or Sc, or group-IV element, Zr or Hf) based on density functional theory. The formation energy has a strong correlation with the atomic radius of R...
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Published in: | Journal of applied physics 2018-10, Vol.124 (16) |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Online Access: | Get full text |
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Summary: | We theoretically study the structural stability of
RFe
12 with the ThMn
12 structure (
R: rare-earth element, La, Pr, Nd, Sm, Gd, Dy, Ho, Er, Tm, Lu, Y, or Sc, or group-IV element, Zr or Hf) based on density functional theory. The formation energy has a strong correlation with the atomic radius of
R. The formation energy relative to simple substances decreases as the atomic radius decreases, except for
R
= Sc and Hf, while that relative to
R
2Fe
17 and bcc Fe has a minimum for
R
= Dy. The present results are consistent with recent experimental reports in which the partial substitution of Zr at
R sites stabilizes
RFe
12-type compounds with
R
= Nd or Sm. Our results also suggest that the partial substitution of Y, Dy, Ho, Er, or Tm for Nd or Sm is a possible way to enhance the stability of the ThMn
12 structure. Under hydrostatic pressure, the formation enthalpy decreases up to
≈6 GPa and then starts to increase at higher pressures. |
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ISSN: | 0021-8979 1089-7550 |
DOI: | 10.1063/1.5050057 |