By using isothermal 4-point electrical resistivity measurements, chemical diffusion coefficients were determined for the in-diffusion and out-diffusion of O to and from epitaxial c-axis oriented films, at temperatures ranging from 500 to 650K. Temporal changes in resistivity, at constant O partial pressure, were monitored following small upward or downward steps in temperature. The same coefficient, 2 x 10-14cm2/s, was found at 600K for both the in-diffusion and out-diffusion of O. The temperature dependence of the diffusivity could be closely fitted by assuming an Arrhenius law. This yielded the same activation energy (1.1eV) for in-diffusion and out-diffusion.

S.Kittelberger, O.M.Stoll, R.P.Huebener: Superconductor Science and Technology, 1998, 11[8], 744-50