材料期刊网

The martensitic transition, magnetocaloric effect ( MCE) and shape memory effect ( MSE) of ferromagnetic Heusler alloys Ni50Mn50-x Sb-x (x = 12, 13 and 14) have been investigated. A large positive magnetic entropy change Delta SM was observed in the vicinity of the martensitic transition. The maximum value of Delta SM is 9.1 J kg(-1) K-1 in Ni50Mn37Sb13 at 287K for a magnetic field change of 5 T. This change originates from the first-order transition from a low-temperature weak-magnetic martensitic phase to a high-temperature ferromagnetic parent phase. A magnetic-field-induced shape recovery strain of about 15 ppm at room temperature and at a relatively low magnetic field ( 1.2 T) was observed to accompany the reverse martensitic transformation. The large field-induced MCE and MSE in the NiMnSb system make it a promising material for room-temperature application.