Universal behavior for magnetic entropy change in magnetocaloric materials: An analysis on the nature of phase transitions

A universal curve for the change in the magnetic entropy has been recently proposed for materials with second-order phase transitions. In this work we have studied the universal behavior of the magnetocaloric effect in the family of cobalt Laves phases, RCo2, and mixed manganites, La-2/3(CaxSr(1-x))(1/3)MnO3, which exhibit first- and second-order phase transitions. The rescaled magnetic entropy change curves for different applied fields collapse onto a single curve for materials with second-order phase transition as opposed to the first- order phase transition compounds, for which this collapse does not hold. This result suggests that the universal curve may be used as a further criterion to distinguish the order of the phase transition.