Phase diagram of the spin-1 XXZ Heisenberg ferromagnet with a single-ion anisotropy

Abstract

Phase diagram of the spin-1 quantum Heisenberg model with both exchange as well as single-ion anisotropy is constructed within the framework of pair approximation formulated as a variational procedure based on the Gibbs-Bogoliubov inequality. In this form adapted variational approach is used to obtain the results equivalent with the Oguchi's pair approximation. It is shown that the single-ion anisotropy induces a tricritical behaviour in the considered model system and a location of tricritical points is found in dependence on the exchange anisotropy strength.

12 pages, 3 figures, preprint submitted to Chin. J. Phys

Cited by in corpus (1)

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