Croatica Chemica Acta, Vol. 86 No. 4, 2013.
Original scientific paper
https://doi.org/10.5562/cca2266
Néel Temperature of Antiferromagnets for Phase Transitions Driven by Spin-wave Interactions
Andrés Ayuela
; Centro de Física de Materiales CFM-MPC CSIC-UPV/EHU;Donostia International Physics Center (DIPC), Departamento de Física de Materiales, Fac. de Químicas, Univ. del Pais Vasco UPV-EHU, 20018 San Sebastián, Spain
Douglas J. Klein
; Marine Sciences, Texas A&M University at Galveston, P.O. Box 1675, Galveston, Texas 77553, USA
Norman H. March
; Donostia International Physics Center (DIPC), Departamento de Física de Materiales, Fac. de Químicas, Univ. del Pais Vasco UPV-EHU, 20018 San Sebastián, Spain;Dept. of Physics, Univ. of Antwerp, Antwerp, Belgium.;Oxford University, Oxford, England
Abstract
In a recent article,1 a wide variety of phase transitions, with transition (t) temperature Tt , were
shown to be usefully characterized by the form kBTt Echar exp1/ λ where λ measured the strength
of the quasiparticle interactions driving the phase transition. The present article is concerned primarily
with antiferromagnets (AFs) having Néel temperature TN. It is first argued that the characteristic energy
Echar can be usefully represented by kBθ, where θ is the Curie-Weiss temperature. This assertion is then
confronted with experimental data on four insulating transition metal oxides, these being selected as all
having the paramagnetic ions on a facecentered cubic lattice. For four of the five θ / TN is certainly greater
than unity, the fifth having the ratio as unity to within experimental error. λ is then argued to be related
to physical parameters entering a mean field approximation to AFs. Finally, the above insulating Afs are
complemented by a brief discussion of a metallic FeRh alloy where, in addition to having itinerant electrons
and antiferromagnetism, elevating the temperature leads to a transition from an AF to a ferromagnetic
state. (doi: 10.5562/cca2266)
Keywords
antiferromagnets; transition metal oxides; Neél temperature; magnons; spin-waves
Hrčak ID:
112778
URI
Publication date:
16.12.2013.
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