Contributions to the entropy change in melt-spun LaFe11.6Si1.4

Abstract

Here we study the calorimetric and magnetic behaviour of melt-spun LaFe11.6Si1.4, a potential magnetic refrigerant material system that exhibits the rare combination of a large entropy change and low thermal and magnetic field hysteresis. We are able to separate the calorimetric contribution from latent heat and changes in equilibrium heat capacity explicitly by using two separate calorimetric probes. The heat capacity of this sample exhibits significant changes of the order of 500–1000 J K−1 kg−1 in response to magnetic field that results in large changes in entropy. The different contributions to entropy change from latent heat and heat capacity are shown to evolve as the material is field driven through its itinerant metamagnetic transition. We demonstrate explicitly that in the melt-spun sample studied here, the majority of the total entropy change comes from the equilibrium change of heat capacity.