A magnetocaloric effect arising from a ferromagnetic transition in the martensitic state in Heusler alloy of Ni50Mn36Sb8Ga6

We report a magnetocaloric effect with nearly zero thermal hysteresis in Heusler alloy of Ni50Mn36Sb8Ga6 around room temperature due to a ferromagnetic transition in martensitic state (FTMS). The refrigerant capacity value of this ferromagnetic transition in the vicinity of onset temperature TCM can arrive at 163.8 J/kg, much higher than that of first-order magnetically martensitic transition in the same alloy. Such a magnetocaloric effect in FTMS is attributed to a second-order (or a weak first-order) transition from an antiferromagnetic phase with modulated 7 M orthorhombic structure to a ferromagnetic phase with modulated 4O orthorhombic structure.