Martensitic Transformation and Magnetocaloric Properties of NiCoMnSn Magnetic Shape Memory Alloys

Abstract

We report on the magnetic, magnetocaloric properties, and hysteresis of Ni45Co5Mn38Sn12 and Ni45Co5Mn38.5Sn11.5 Heusler polycrystalline alloys under several magnetic field values. Both alloys have a moderate magnetization difference ( approximate to 70 emu/gr) between austenite and martensite phase with a moderate thermal hysteresis ( approximate to 8 K) around the martensitic transition. Magnetic field dependent measurements reveal that the application of a magnetic field stabilizes the austenite phase, which has higher magnetization. Both alloys have substantial inverse magnetic entropy changes and adiabatic temperature changes. In addition, we investigate the accessibility of the calculated entropy change that is quantified by means of the minimum magnetic field required to start and to complete the magnetostructural phase transition.