Magnetic field dependence of the martensitic transition and magnetocaloric effects in Ni49BiMn35In15

The structural, magnetic, and magnetocaloric properties of the Bi-doped Heusler alloy Ni49BiMn35In15 have been investigated using room temperature X-ray diffraction (XRD) and magnetization measurements in a temperature interval of 5-400 K. The alloy at room temperature was found to be in a mixture of a high temperature austenite phase (AP) and a low temperature martensite phase (MP). A drastic shift in the martensitic transition temperature at the rate of 16 K/T from 197 K to lower temperatures was observed. A kinetic arrest phenomenon of the AP was observed in the magnetization and electrical resistivity measurements during field-cooled (FC) measurements at 5T. A metamagnetic behavior characterized by a jump in magnetization in the isothermal M(H) curves near TM was observed. The maximum value of the magnetic entropy change and refrigerant capacity at Curie temperature were found to be 5.5 Jkg-1K-1 and 312 Jkg-1 for μoΔH = 5T, respectively. A large magnetoresistance value of -56% was found near the martensitic transition.