Microstructures and magnetic property in Mn-rich off-stoichiometric Mn2NiGa Heusler alloys

Microstructure and magnetic properties were investigated in Mn50+xNi25Ga25−x ferromagnetic shape memory alloys. Some Mn-rich precipitates were observed in polycrystalline samples after being annealed at 1073 K for 24 h, and 1123 K for 24 h is required for a single martensitic phase. The saturation magnetization substantially decreases with higher Mn content and higher annealing temperature at which no precipitates were found in a field up to 50 KOe.