Room temperature inverse magnetocaloric effect in Pd substituted Ni50Mn37Sn13 Heusler alloys

The structural, magnetic and magnetocaloric effects for Ni50−xPdxMn37Sn13 Heusler alloys have been investigated around both structural and magnetic transitions. The room temperature X-ray diffraction indicates 10 M modulated martensitic structure with an orthorhombic unit cell for x=0 and 1. However, the superstructure reflections for x=2 alloy imply that the pattern is related to the L21 phase. The maximum entropy change occurring at the martensitic transition is found to be 21 J kg−1 K−1 for Ni50Mn37Sn13 alloy around room temperature. Despite the smaller change in entropy around room temperature, 3.8 times larger value of refrigerant capacity (184.6 J/kg) is achieved for 2% substitution of Pd, due to occurrence of magnetic entropy change in a broader temperature region.