Tuesday, April 9, 2013

1304.2034 (Karol Szałowski et al.)

Thermodynamic properties of a diluted Heisenberg ferromagnet with
interaction anisotropy -- magnetocaloric point of view
   [PDF]

Karol Szałowski, Tadeusz Balcerzak, Andrej Bobák
The thermodynamics of a site-diluted ferromagnetic Heisenberg model for spin $S=1/2$ with interaction anisotropy in spin space is investigated. The study is aimed at presenting the magnetocaloric properties of such a model, including the entropy and temperature changes in magnetization/demagnetization processes, generalized Gr\"uneisen ratio as well as the quantities characterizing the efficiency of magnetic cooling cycles. The results are obtained using Pair Approximation (PA) method and extensively compared with the Molecular Field Approximation (MFA) calculations. The importance of interaction anisotropy and site-dilution is discussed. The inadequacy of the MFA approach (even on the qualitative level) is found for selected quantities, while PA provides the results which are consistent with the experimentally observed behaviour.
View original: http://arxiv.org/abs/1304.2034

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