Magnetoresistance in ferromagnetic shape memory alloy NiMnFeGa

► NiMnFeGa melt-spun ribbon exhibited GMR effect with a large negative MR up to −13%. ► GMR behavior is arising from the spin-dependent scattering from magnetic inhomogeneities. ► In the absence of these magnetic inhomogeneities, Heusler alloys seem to show a common linear MR behavior at around 0.8TC. ► Conventional AMR behaviors due to the spin-orbital coupling are observed in NiMnFeGa single crystal and Ni2FeGa ribbon samples at low temperatures.