High-temperature metamagnetic martensitic transformation in fairly Mn-rich Ni_50−xCo_xMn₃₇Ga₁₃ (0 ≤ x ≤ 50) alloys

Fairly Mn-rich Ni_50−xCo_xMn₃₇Ga₁₃ (0 ≤ x ≤ 50) alloys were investigated with the microstructure, phase transition and magnetic properties. A metamagnetic martensitic transformation with a large magnetization change of up to 40 Am² kg⁻¹ was found in a dual-phase Ni₃₀Co₂₀Mn₃₇Ga₁₃ alloy at 500 K which is the highest temperature as reported. Additionally, the mechanical properties of the alloys were improved by the dual-phase microstructure. This work is expected to widen the application of ferromagnetic shape memory alloys in areas, such as high temperature thermoelectric conversion of industrial waste heat and extreme environments such as aerospace.