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The Validity of the Low‐Temperature Expansions for the Anisotropic Heisenberg Models
Author(s) -
Škeinjar M. T.,
Kapor D. V.,
Šetrajčić J. P.
Publication year - 1984
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.2221220114
Subject(s) - anisotropy , dimensionless quantity , heisenberg model , ising model , condensed matter physics , magnetization , physics , order (exchange) , specific heat , anisotropy energy , magnetic anisotropy , thermodynamics , quantum mechanics , ferromagnetism , magnetic field , finance , economics
The low‐temperature expansion of the relative magnetization of two anisotropic Heisenberg models is discussed. It is shown that due to the existence of the temperature independent energy gap, the dimensionless temperature cannot be applied as the small parameter. In other words the low‐temperature expansion is completely invalid for the Heisenberg model with the Ising anisotropy. For the anisotropic model proposed by Belorizky et al. one can make calculations in the first order in the anisotropy parameter, but there is no term of order T 3 as previously stated.