Reverse magnetostructural transformation and adiabatic temperature change in Co- and In-substituted Ni-Mn-Ga alloys

A careful characterization of the magnetocaloric effect in Co-substituted Ni-Mn-Ga Heusler alloys, based both on direct and indirect methods, is presented. In the present paper, adiabatic temperature change values ( Delta T sub(ad)) up to 1.6 K in 1.9 T were measured across the magnetostructural transformations. The studied samples, with similar transformation temperatures and comparable entropy changes, show surprising differences of the Delta T sub(ad). In order to gain better insight into the behavior of the Delta T sub(ad) peak values among different samples, a qualitative model is proposed based on magnetization and magnetothermal data.