By using electron paramagnetic resonance techniques, the motion of O vacancies within the O octahedron of the perovskite was detected via the alignment of O vacancy-related defect dipoles. The vacancy motion was found to have an associated activation energy of 0.91eV. It was noted that the onset of a degradation of the resistance was concurrent with O vacancy motion. It was suggested that O vacancy migration in the lattice was responsible for the observed degradation.

Oxygen Vacancy Motion in Perovskite Oxides. W.L.Warren, K.Vanheusden, D.Dimos, G.E.Pike, B.A.Tuttle: Journal of the American Ceramic Society, 1996, 79[2], 536-8