aCentro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, Rio de Janeiro, 22290-180 RJ, Brazil
bUniversidade do Estado do Rio de Janeiro, Rua São Francisco Xavier 524, Rio de Janeiro, 20550-013 RJ, Brazil
Abstract:
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 ΔS and ΔTad 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 ΔS and ΔTad but also the specific heat capacity.