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(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(ad). In order to gain better insight into the behavior of the Delta T(ad) peak values among different samples, a qualitative model is proposed based on magnetization and magnetothermal data.