Enhanced magnetoresistance through magnetic-field-induced phase transition in Ni2MnGa co-doped with Co and Mn

Abstract We report the observation of giant negative magnetoresistance up to −46% at 60 kOe magnetic field in Ni 1.68 Co 0.32 Mn 1.20 Ga 0.80 alloy, which is about 5 times larger than that reported in Ni–Mn–Ga alloys. The significant change in resistivity during martensitic transformation originates from the altered electronic structure due to the change of magnetic state. The magnetic-field-induced phase transition from partially antiferromagnetic martensite to ferromagnetic austenite is responsible for the enhanced magnetoresistance.