A wide temperature window for the magnetostructural transformation in Mn50Ni50-x-ySnxCoy alloys

In order to open a wide temperature window for a magnetostructural transformation, Sn-Co co-doping was explored in the Mn50Ni50 alloy. The experimental results show that doping with Sn and doping with Co have different effects on the martensitic and austenitic structures, the martensitic transformation, the thermal hysteresis and the magnetic properties of the martensitic and austenitic phases. By tuning the Sn and Co content in Mn50Ni50−x−ySnxCoy from x = 11, y = 0 to x = 6, y = 14, the martensitic transformation temperature, Tm, could be adjusted over the range from 99 K to 450 K, with the condition that Tm remains lower than the Curie temperature of the austenitic phase, Tca, which varied from 288 K to 565 K. Thus, a 351 K temperature window for the magnetostructural transformation was established and a series of ferromagnetic shape memory alloys was identified.