It was found that chemical diffusion coefficients could be reliably measured in these electronic and ionic conductors by using a contactless optical relaxation technique which permitted the inclusion of internal trapping effects. This led to a consistent analysis of the chemical diffusion coefficient in terms of temperature, O partial pressure and doping level. In both materials, the agreement between experiment and theory was very good. In the former material, due to the availability of the necessary parameters, no adjustable factor was required. Overall, the analysis also led to a re-evaluation of published data and permitted the reconciliation of an apparent scatter in previous results.

T.Bieger, H.Yugami, N.Nicoloso, J.Maier, R.Waser: Solid State Ionics, 1994, 72, 41-6