Spin valve like behaviour in Co₂NbAl with anti-site disorder: Experiment and theory

The regulation of spin-polarized current remains a cornerstone in spintronic research, with spin-valves serving as a potent avenue to manipulate these currents via applied magnetic fields. Asymmetric magnetoresistance (MR) against applied magnetic field is the experimental signature of the spin valve effect. Our study proposes a full Heusler alloy Co₂NbAl, as a promising half metallic spin-valve, where the spin-valve feature, unlike in magnetic multilayer heterostructures, persists across a very wide field range. Co₂NbAl crystallizes in the proto-type structure with a partial anti-site disorder. Magnetization data indicates the ferromagnetic behaviour and the magneto-transport properties hints about the half metallic nature of this alloy. The asymmetry in magneto-resistance is observed from very low to room temperature for the entire applied field range and we emphasize on the possible origin of such a robust asymmetry. Our computational analysis helps us to disclose the role of the anti-site disorder in developing the interfaces of magnetically competing phases which eventually is responsible for the spin valve effect. The half metallicity is also found to be robust against the anti-site disorder.