Emergent metal-insulator transition in Fe-doped LaNiO₃ thin films on glass substrate

Transition-metal-oxide based perovskites belong to the strongly correlated electron system exhibiting composition dependent metal-insulator transition. Their electronic properties can be tuned by doping them with right material by right amount for application in the diverse areas of material science. This article presents the preparation of crystalline thin films of Fe-doped LaNi_1-xFe_xO₃ (x = 0, 0.1, 0.2, 0.4) on glass substrate by spin-coating of chemical solutions. Annealing the films at a suitable temperature for optimum time plays a crucial role in obtaining good crystalline samples. We performed structural characterizations of the films using X-ray diffraction spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Electrical conductivity of the films was measured by four-probe technique at 30˚ C, 50˚ C, 80˚ C, and 100˚ C. We observed a non-ohmic insulating behaviour for the sample with x = 0.4 while all the other films with lower doping level showcased linear voltage-current relationship with metallic temperature dependence.