Optical absorption relaxation applied to SrTiO₃ and ZrO₂: An in-situ method to study trapping effects on chemical diffusion

Chemical diffusion coefficients have been reliably measured in the case of the electronic conductor SrTiO₃ (Fe-doped) and the ionic conductor yttria-stabilized ZrO₂ (Ni-doped) by using a contactless optical relaxation technique. A quantitative concept (proposed by one of us earlier) which allows the inclusion of internal trapping effects leads to a consistent analysis of D̃ in terms of temperature (T), oxygen partial pressure (P) and doping level (m). In both materials, SrTiO₃ and ZrO₂, the argument between experiment and theory is very good. In the first case, due to the availability of all the necessary parameters, no adjusting parameter has been used. In both cases, the analysis also leads to a reevaluation of literature data and is able to reconcile the apparent "scatter" of published results.