Influence of Internal Reactions on Chemical Diffusion: Application to Fe-Doped SrTiO_3

摘要

Valence changes of ionic defects (trapping effects) play an essential role with respect to chemical diffusion in many electronically or mixed conducting materials e.g. SnO_2, PbO, Yba_2 Cu_3O_6 + x, SrTiO_3, as well as in ionic conductors (e.g. ZrO_2). Following the concept of "Conservative Ensembles", it is shown how short-range interac- tions can be explicitly handled in the chemical diffusion formalism if they are in local equilibrium with the minority carriers. It is also outlined how they influence electrochemical polarisation or tracer experiments.