Transference Numbers for In‐Plane Carrier Conduction in Thin Film Nanostructured Gadolinia‐Doped Ceria Under Varying Oxygen Partial Pressure

Abstract

We demonstrate a modified Hebb–Wagner approach to quantitatively estimate transference numbers for carrier conduction in thin film oxide conductors using blocking electrodes in an in‐plane geometry. We report ionic transference numbers, ti, for gadolinia‐doped ceria (GDC) thin films, a model mixed ion–electron conductor, at 973K and oxygen partial pressure ranging from 0.21 atm down to approximately 10−22 atm. Our results indicate that GDC reaches the electrolytic regime (ti=0.5) at an oxygen partial pressure of 5 × 10−19 atm at 973K. This approach may be useful for understanding carrier transport mechanisms in low‐dimensional oxide heterostructures with specific relevance to nanostructured energy materials.