The influence of the quadrupolar interaction in the magnetocaloric effect

Using a model Hamiltonian, which takes into account the dipolar and quadrupolar interaction within the molecular field approximation, it was possible to investigate the influence of a magnetic phase transition on the magnetocaloric potential. The results obtained show that discontinuous changes in the order parameters associated with the first-order phase transition involve a strong enhancement in magnetocaloric potential (which has practical importance for magnetic refrigeration efficiency) at the critical temperature. These results were fully discussed and correlated with the Maxwell thermodynamic relations.