Influence of tensile-strain-induced oxygen deficiency on metal-insulator transitions in NdNiO(3−δ) epitaxial thin films

We report direct evidence that oxygen vacancies affect the structural and electrical parameters in tensile-strained NdNiO(3−δ) epitaxial thin films by elaborately adjusting the amount of oxygen deficiency (δ) with changing growth temperature T (D). The modulation in tensile strain and T (D) tended to increase oxygen deficiency (δ) in NdNiO(3−δ) thin films; this process relieves tensile strain of the thin film by oxygen vacancy incorporation. The oxygen deficiency is directly correlated with unit-cell volume and the metal-insulator transition temperature (T (MI)), i.e., resulting in the increase of both unit-cell volume and metal-insulator transition temperature as oxygen vacancies are incorporated. Our study suggests that the intrinsic defect sensitively influences both structural and electronic properties, and provides useful knobs for tailoring correlation-induced properties in complex oxides.