Interfacial engineering of Fe3O4/reduced graphene oxide nanocomposites for spintronic applications

Interface-engineered hybrid nanocomposites offer considerable potential for spintronic applications, yet their spin-dependent transport mechanisms remain poorly understood. Here, we report the solvothermal synthesis of Fe3O4/reduced graphene oxide (RGO) nanocomposites, in which ∼25 nm Fe3O4 nanoparticles are uniformly dispersed on conductive RGO sheets. The nanocomposites exhibit a 250-fold decrease in room-temperature resistance, and their low-temperature charge transport is dominated by disorder-driven, non-ideal hopping conduction associated with interfacial coupling and percolative transport pathways, as revealed by Zabrodskii analysis. Magnetotransport measurements (2–300 K, up to 9 T) show a crossover from negative to positive magnetoresistance, reaching +2.0% at 2 K, which is five times larger than that of pristine Fe3O4. The magnetoresistance behavior is interpreted in terms of competing spin-dependent scattering and field-enhanced localization in the disordered Fe3O4/RGO network. These findings demonstrate that Fe3O4/RGO nanocomposites provide a versatile platform for controlling spin-dependent transport through interfacial and disorder engineering.