Specific heat and the influence of hydrostatic pressure on the phase transitions in Ni50Mn35In14.25B0.75

The magnetic properties, magnetocaloric effects, and martensitic transition in Ni50Mn35In14.25B0.75 have been investigated using specific heat and magnetic measurements as a function of hydrostatic pressure. A shift in the martensitic transition temperature (TM) toward room temperature (by 25 K to higher temperature) was observed with the application of pressure (P=0.54 GPa). The isothermal entropy changes obtained from magnetization and heat capacity measurements were found to be in good agreement. A large inverse adiabatic temperature change (ΔTad) of 2.7 K was found from heat capacity data at TM for a magnetic field change of 1.8 T. The density of states and the Debye temperature were found to be 4.9 states/eV/f.u. and 322 K, respectively. The magnetic entropy analysis agrees fairly well with the theoretical maximal magnetic entropy, R ln(2J+1).