The out-diffusion of O during the heat treatment of fully oxygenated c-axis oriented epitaxial films led to the creation of high electric fields in the films. During heat treatment under an O pressure, a transient electric resistance peak was also observed.

K.Hauser, S.Kittelberger, R.P.Hübener, E.Haufe, T.Schwellinger: Journal of Low Temperature Physics, 1996, 105[5-6], 1409-14