Monte Carlo calculations of the magnetocaloric effect in gadolinium

In this work we discuss the magnetocaloric effect in metallic gadolinium. We use a model Hamiltonian of interacting 4f spins and treat the 4f spin-spin interaction both in the mean field approximation and in the Monte Carlo simulation. The calculations show that the mean field approximation yields reasonable results for the magnetocaloric potentials Delta S and Delta T-ad but it fails in explaining the experimental data of specific heat at the magnetic ordering temperature. On the other hand, our theoretical results show that the Monte Carlo calculation describes well not only the magnetocaloric potentials Delta S and Delta T-ad but also the specific heat capacity. (c) 2008 Elsevier B.V. All rights reserved.