COUPLING BETWEEN IONIC AND ELECTRONIC FLUXES IN MIXED IONIC ELECTRONIC CONDUCTORS - EXPERIMENTS ON CO1-DELTA-O/

In investigations of the isothermal transport properties of mixed cond uctors the dynamical coupling between ionic and electronic partial flu xes is usually neglected. Within the formalism of (linear) irreversibl e thermodynamics this assumption is expressed by a vanishing cross coe fficient L(12) in the matrix of the phenomenological transport coeffic ients, By analysing the phenomenological flux equations for cation vac ancies and electron holes, experiments for the determination of the cr oss coefficient are defined. Experimental results for the coupling eff ect in Co1-deltaO are presented, which have been obtained from three i ndependent techniques. The results are discussed in the light of previ ous theoretical considerations. It is shown that a strong coupling bet ween cation vacancies and electron holes exists in the case of C1-delt aO. To account for this coupling, an effective charge number of ions h as to be introduced for use in the formulation of ionic fluxes.