Catalytic Hydrogen Doping of NdNiO₃ Thin Films under Electric Fields

The electric-field-assisted hydrogenation and corresponding resistance modulation of NdNiO₃ (NNO) thin-film resistors were systematically studied as a function of temperature and dc electric bias. Catalytic Pt electrodes serve as triple-phase boundaries for hydrogen incorporation into a perovskite lattice. A kinetic model describing the relationship between resistance modulation and proton diffusion was proposed by considering the effect of the electric field during hydrogenation. An electric field, in addition to thermal activation, is demonstrated to effectively control the proton distribution along its gradient with an efficiency of ∼22% at 2 × 10⁵ V/m. The combination of an electric field and gas-phase annealing is shown to enable the elegant control of the diffusional doping of complex oxides.