Magnetic, electrical, and magnetothermal properties in Ni–Co–Mn–Sb Heusler alloys

Abstract

We have studied the magnetic, magnetoresistance, and thermal properties of Ni50−xCoxMn38Sb12 for x=0–7. The martensitic transition temperature decreases with increase in x and there is no martensitic transition observed for x=8. The martensitic transition is accompanied by a large change in magnetization as well as in electrical resistance. Due to the large change in magnetization, a large magnetic entropy change in 68 and 43 J kg−1 K−1 is observed for x=5 and 4, respectively, around the room temperature. A large magnetoresistance of 34% is observed for x=7. Both the magnetocaloric effect and the magnetoresistance are associated with the martensitic transition, which can be tuned significantly by varying the Ni/Co composition. The results obtained in this system suggest that it may act as a potential magnetic refrigerant as well as a magneto resistive material.