Convergence of direct and indirect methods in the magnetocaloric study of first ordertransformations: The case of Ni-Co-Mn-Ga Heusler alloys

The study of two aspects of the magnetocaloric effect (MCE), namely, the matching between isothermalentropy change and direct adiabatic temperature change, is not straightforward since huge differences betweenthese two quantities have often been reported. Here we put in relation the direct and indirect measurements on thefirst order magnetostructural martensitic transformation occurring in Ni-Co-Mn-Ga alloys. In order to completethe characterization of the MCE and to find an explanation of these mismatches, differential scanning calorimetermeasurements have been performed at different applied magnetic fields