Abstract:
In this work, we report the effect of hydrostatic pressure (P) on the martensitic transition in Mn50Ni40Sn10 Heusler alloy using the magnetization and electrical resistivity measurements. Martensitic transition temperature (T-M) is found to shift significantly to higher temperatures with the application of pressure, which reflects the stabilization of the martensite phase. On the other hand, T-M shifts to lower temperatures with magnetic field, which implies the stabilization of the austenite phase. The estimated rate of change of martensitic transition temperature with pressure (dT(M)/dP) for the present alloy is similar to 4.6 K/kbar. The alloy shows a maximum negative magnetoresistance (MR) of 9.6% for P = 4 kbar at the martensitic transition. A large isothermal magnetic entropy change (Delta S-M) of 16.6 J/kg.K and a refrigerant capacity (RC) of similar to 146 J/kg are observed at TM under ambient pressure. Both quantities are found to decrease with the increase of pressure. The values of Delta S-M and adiabatic temperature change (Delta T-ad), calculated from heat capacity measurements are similar to 11.3 J/kg. K and -3.4 K respectively for 50 kOe field change. The observed pressure and field dependence results have been explained using the Clausius-Clapeyron equation. The combined effect of pressure and field on the martensitic transition is also discussed.