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, $R{\text{Co}}_2$, and mixed manganites, ${\text{La}}_{2/3}{\left({\text{Ca}}_x{\text{Sr}}_{\left(1-x\right)}\right)}_{1/3}{\text{MnO}}_3$, 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.

• Received 29 September 2009

DOI:https://doi.org/10.1103/PhysRevB.81.224424