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Variational Treatment of Anisotropic Heisenberg Antiferromagnets
Author(s) -
Figueiredo W.,
Gitahy V. H.,
Salinas S. R.
Publication year - 1980
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221020213
Subject(s) - anisotropy , isotropy , orthorhombic crystal system , physics , antiferromagnetism , condensed matter physics , mathematical physics , quantum mechanics , diffraction
A simplified version of Falk's variational treatment of the isotropic Heisenberg antiferromagnet is extended by taking into account both, exchange and single‐ion uniaxial and orthorhombic anisotropic interactions. Expressions are obtained for the low‐temperature canted‐paramagnetic phase boundary. For uniaxial anisotropies the expression is of the form à – B̃T 3/2 – C̃T 5/2 – …, and for orthorhombic anisotropies it is of the form \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \alpha \limits^ \sim $\end{document} – \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \beta \limits^ \sim $\end{document} T 2 – …. The structure coefficients Ã, B̃, \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \alpha \limits^ \sim $\end{document} , and \documentclass{article}\pagestyle{empty}\begin{document}$ \mathop \beta \limits^ \sim $\end{document} agree with previous spin‐wave calculations.