OPTICAL-ABSORPTION RELAXATION APPLIED TO SRTIO3 AND ZRO2 - AN IN-SITUMETHOD TO STUDY TRAPPING EFFECTS ON CHEMICAL DIFFUSION

Chemical diffusion coefficients have been reliably measured in the cas e of the electronic conductor SrTiO3 (Fe-doped) and the ionic conducto r yttria-stabilized ZrO2 (Ni-doped) by using a contactless optical rel axation technique. A quantitative concept (proposed by one of us earli er) which allows the inclusion of internal trapping effects leads to a consistent analysis of (D) over tilde in terms of temperature (T), ox ygen partial pressure (P) and doping level (m). In both materials, SrT iO3 and ZrO2, the argument between experiment and theory is very good. In the first case, due to the availability of all the necessary param eters, no adjusting parameter has been used. In both cases, the analys is also leads to a reevaluation of literature data and is able to reco ncile the apparent ''scatter'' of published results.