The Effect of Partial Substitution of Ni by Co on the Magnetic and Electrical Properties of Ni50Mn35In15 Heusler Alloy

In this paper, we have explored the effects of the partial substitution of Ni for a small amount of Co in Ni50Mn35In15 on its structural, magnetic, and electrical properties by using room temperature X-ray diffraction, temperature- and field-dependent magnetization, M(T, H), and resistivity rho(T, H) measurements in magnetic fields up to 5 T, and in the temperature interval 5-400 K. A small amount of Co (similar to 4%) doping in the Ni site decreases T-M and increases T-C. For Ni48Co2Mn35In15, a large MR was found to be about -53% at Delta H = 1 T (at T = 275 K) and more than -70% at the same temperature for Delta H = 5 T. The substitution of Co in the Ni position enhances the magnetization jump up to 77 emu/g across the martensitic transformation. Magnetization measurements revealed that the large magnetoresistance value could be due to a metamagnetic-like transition, where the system transforms from a state that contains antiferromagnetically coupled regions to a purely ferromagnetic state. The change in magnetic and electrical properties due to the doping of the Co atom in Ni-Mn-In-based Heusler alloys is discussed in this paper.