arXiv:1009.4411 · Journal of Statistical Mechanics Theory and Experiment
The magnetocaloric effect in integrable spin-schains
G A P Ribeiro
Abstract
We study the magnetocaloric effect for the integrable antiferromagnetic high spin chain. We present an exact computation of the Grüneisen parameter, which is closely related to the magnetocaloric effect, for the quantum spin- s chain in the thermodynamical limit by means of Bethe ansatz techniques and the quantum transfer matrix approach. We have also calculated the entropy S and the isentropes in the ( H , T ) plane. We have been able to identify the quantum critical points H c ( s ) = 2/( s + 1/2) looking at the isentropes and/or the characteristic behaviour of the Grüneisen parameter.