Conductivity measurements were performed on SrCe0.95Yb0.05O3 using controlled O partial pressures and temperatures. A defect model was proposed which was consistent with the experimental results and which allowed for PO2-¼-dependent n-type, PO2-independent O-ion and PO2¼-dependent p-type conductivity components. On the basis of the measurements, and this defect model, it was concluded that the electrical properties of this material were markedly dependent upon the stoichiometry. It was found that the electrical properties were controlled by holes, O vacancies and electrons at high, intermediate and low O partial pressures, respectively. Analysis of the data indicated that the activation energy for O ion migration was equal to 0.77eV. It was concluded that earlier reports of an insensitivity to the O partial pressure were misguided, and were instead due to a coincidental similarity of the magnitudes of the n-type and p-type conductivities.

I.Kosacki, H.L.Tuller: Solid State Ionics, 1995, 80[3-4], 223-9