The effects of substituting Ag for In on the magnetoresistance and magnetocaloric properties of Ni-Mn-In Heusler alloys

The effect of substituting Ag for In on the structural, magnetocaloric, and thermo-magnetic properties of Ni50Mn35In15-xAgx (x = 0.1, 0.2, 0.5, and 1) Heusler alloys was studied. The magnitude of the magnetization change at the martensitic transition temperature (T-M) decreased with increasing Ag concentration. Smaller magnetic entropy changes (Delta S-M) were observed for the alloys with larger Ag concentrations and the martensitic transition shifted to higher temperature. A shift of T-M by about 25 K to higher temperature was observed for an applied hydrostatic pressure of P = 6.6 kbar with respect to ambient pressure. A large drop in resistivity was observed for large Ag concentration. The magnetoresistance was dramatically suppressed due to an increase in the disorder of the system with increasing Ag concentration. Possible mechanisms responsible for the observed behavior are discussed. (C) 2016 Author(s).