Martensitic transition, inverse magnetocaloric effect and shape memory characteristics in Mn48−xCuxNi42Sn10 Heusler alloys

In this paper, we have systematically prepared a serials of polycrystalline Mn48−xCuxNi42Sn10 alloys (x=0, 1, 3, 5, 6, 8, 10 and 12) and investigated the influence of the Cu doping on martensitic transition (MT) as well as magnetic properties. Experimental results indicate that the MT temperature and the martensite Curie temperature (TcM) shift to high temperature with increasing the substitution of Cu (from Mn rich alloy to Ni rich alloy), while the austenite Curie temperature (TcA) is almost unchanged. It was found that the structures undergo L21 and 4O with the increasing of Cu concentration near room temperature. Therefore, the magnetostructural transition can be tuned by appropriate Cu doping in these alloys. Moreover, we mainly studied the multiple functional properties for inverse magnetocaloric effect and shape memory characteristics associated with the martensitic transition. A large positive isothermal entropy change of Mn48Ni42Sn10 was obtained, and the maximum transition entropy change achieves about 48 J/kg K as x=8. In addition, a considerable temperature-induced spontaneous strain with the value of 0.16% was obtained for Mn48Ni42Sn10 alloys.