Microstructure and magnetic properties of as-cast Ni2MnGa alloys processed by twin roller melt spinning

► Ni2MnGa shape memory alloys are synthesized by twin roller melt spinning. ► At 300 K, the major phase is the ferromagnetic cubic L21 Ni2MnGa ordered phase. ► Small Mn(S,Se) precipitates are uniformly dispersed in the austenitic phase. ► The alloys transform to a cubic phase at ∼225 K and to a martensitic phase at ∼130 K. ► Two susceptibility peaks are detected when the martensitic phase demagnetizates.