Large inverse magnetocaloric effect and magnetoresistance in nickel rich Ni52Mn34Sn14 Heusler alloy

Nickel rich Ni52Mn34Sn14 Heusler alloy was prepared by arc melting and subsequent homogenization by annealing. Existence of first order magneto-structural transition (FOMST) was confirmed by various measurements. In comparison to conventional Ni50−xMn36+xSn14 alloys, a larger magnetic entropy change (∆SM≈8 J/kg K using Maxwell׳s thermodynamic equation and ∆SM≈18 J/kg K using Clasius-Clapeyron equation) and large negative magnetoresistance (MR≈−30%) were observed in the vicinity of martensitic transition temperature due to a change of 3 T and 8 T magnetic fields respectively. Effect of excess Ni content was discussed by considering other nearer compositions as reported by other researchers. Irreversibility in FOMST due to kinetic arrest was also studied from MR vs magnetic fields curves taken at a single temperature in two different initial phases. The exchange bias behavior in this alloy was studied by various magnetic measurements.