Influence of Ni/Mn concentration on the structural, magnetic and magnetocaloric properties in Ni50−xMn37+xSn13 Heusler alloys

We report the structure, magnetism and magnetic entropy change in a Mn-rich Ni50−x Mn37+x Sn13 Heusler alloy system in the composition range 0 ⩽ x ⩽ 4. An excess Mn content stabilizes the cubic austenite phase at room temperature. Martensitic transition decreases from 305 to 100 K with increasing Mn concentration (x: 0 → 4) and also it was found to shift to a lower temperature with the application of a higher magnetic field. The exchange bias blocking temperature was found to decrease drastically from 149 to 9 K with increasing Mn concentration. A large magnetic entropy change (ΔS M) of 32 J kg−1 K−1 has been achieved for a field change of 5 T in the x = 3 alloy.