Magnetic field-induced martensitic transformation and large magnetoresistance in NiCoMnSb alloys

Abstract

Magnetic field-induced martensitic transformation was realized in Ni50−xCoxMn39Sb11 alloys. The partial substitution of Co for Ni has turned the antiferromagnetically aligned Mn moments in the starting material Ni50Mn39Sb11 into a ferromagnetic ordering, raising the magnetization at room temperature from 8emu∕g for NiMnSb to ∼110emu∕g for Ni41Co9Mn39Sb11. In the same quaternary sample, a magnetization difference up to 80emu∕g was measured across the martensitic transformation, and the transformation temperature (T0=259K) could be lowered by 35K under a field of 10T. Also a magnetoresistance over 70% was observed through this field-induced transformation.