Handling mixed-state magnetization data for magnetocaloric studiesa solution to achieve realistic entropy behaviour

S Das (1) , J S Amaral (1, 2) , V S Amaral (1)

1 Departamento de Fisica [Aveiro]
2 DFA/FCUP - Departamento de Física e Astronomia [Porto]

We present how to extract a realistic magnetic entropy value from nonequilibrium magnetization data near the transition temperature of a typical first-order system with mixed phase state, influenced by the phase transformation, which is responsible for large values reported, even higher than the theoretical limit. The effect of the mixed phase state is modelled in the magnetization and its nonphysical contribution is removed to obtain the magnetic entropy in accordance with calorimetric experiment and theoretical simulation. This approach gives a reliable estimation of the magnetic entropy value incorporating experimental nonequilibrium magnetization data and correcting the use of Maxwell´s relation.

Mots clés: Physical Sciences

S Das, J S Amaral, V S Amaral. Handling mixed-state magnetization data for magnetocaloric studiesa solution to achieve realistic entropy behaviour. Journal of Physics D: Applied Physics, 2010, 43 (15), pp.152002. ⟨10.1088/0022-3727/43/15/152002⟩. ⟨hal-00569573⟩