Effect of partial substitution of In with Mn on the structural, magnetic, and magnetocaloric properties of Ni 2 Mn 1+ x In 1− x Heusler alloys

The structural, magnetic and magnetocaloric properties of Ni 2 Mn 1+ x In 1− x alloys, prepared using an arc-melting furnace in an argon environment, have been studied for their potential application in cost-effective magnetic refrigeration technology. The room-temperature x-ray diffraction shows that the Ni 2 Mn 1+ x In 1− x alloys with 0 ⩽ x ⩽ 0.34 exhibit austenite cubic phase, whereas the alloys with x > 0.34 have mixed tetragonal martensite and cubic austenite phases. The Ni 2 Mn 1.34 In 0.66 alloy shows a clear second-order phase transition with a Curie temperature of 305 K but its elemental composition is very close to the critical composition between first and second–order phase transitions. The calculated magnetic entropy change and relative cooling power of the Ni 2 Mn 1.34 In 0.66 alloy measured at 3 T field are 4.5 J kg −1 K −1 and 201 J kg −1 , respectively. The temperature dependent resistivity of Ni 2 Mn 1.34 In 0.66 alloy measured at H = 0 Oe shows that the sample has a room temperature resistivity of 7 The absence of thermal and magnetic hysteresis due to second-order magnetic phase change, coupled with higher values of magnetic entropy change and relative cooling power, suggests that the Ni 2 Mn 1.34 In 0.66 alloy has the potential for magnetic refrigeration.