Direct Measurements of Field-Induced Adiabatic Temperature Changes Near Compound Phase Transitions in Ni–Mn–In Based Heusler Alloys

The adiabatic temperature changes (ΔTad) in the vicinity of the Curie and martensitic transition temperatures of Ni50Mn35In15 and Ni50Mn35In14Z (Z = Al and Ge) Heusler alloys have been studied using an adiabatic magnetocalorimeter of 250–350 K temperature interval for applied magnetic field changes up to ΔH = 1.8 T. The largest measured changes were ΔTad = −2 and 2 K near the martensitic (first-order) and ferromagnetic (second-order) transitions for ΔH = 1.8 T, respectively. It was observed that |ΔTad| ≈ 1 K for relatively small field changes (ΔH = 1 T) for both types of transitions. The results indicate that these materials should be further explored as potential working materials in magnetic refrigeration applications