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Magnetochemical origin for Invar anomalies in iron-nickel alloys
Physical Review B (2002)
  • V. Crisan
  • P. Entel
  • H. Ebert
  • H. Akai, Osaka University
  • Duane D. Johnson, University of Illinois at Urbana-Champaign
  • J. B. Staunton, University of Warwick
Zero- and finite-temperature (T) first-principles calculations versus composition (c) show that magnetochemical effects lead to Invar anomalies in Fe-(Ni, Co, Pt) alloys. Chemical short- or long-range order and negative interatomic exchange interaction of electrons in antibonding majority-spin states force the face-centered-cubic lattice to compete simultaneously for a smaller volume (from antiferromagnetic tendencies) and a larger volume (from Stoner ferromagnetic tendencies). The resulting additional negative lattice anharmonicity is very large for Fe-(Ni, Co) while absent for Fe-Pt. Our results explain the T- and c-dependent behavior of Invar properties, including the lattice softening and thermal expansion of Fe-Ni. In addition, the occurrence of a noncollinear spin structure at T=0 K near Invar can be understood on the basis of our results.
Publication Date
July 1, 2002
Publisher Statement
Copyright 2002 American Physical Society
Citation Information
V. Crisan, P. Entel, H. Ebert, H. Akai, et al.. "Magnetochemical origin for Invar anomalies in iron-nickel alloys" Physical Review B Vol. 66 Iss. 1 (2002)
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