Point defects in oxide solid solutions (III) mobilities of cations and vacancies in (Co, Ni)O‐ and (Co, Mg)O‐solid solutions and the calculation of correlation factors

Abstract

AbstractCorrelation effects in the diffusion of cations of B 1‐type solid solutions (A,B)O are discussed on the basis of the different elementary jump frequencies of these cations. In the theoretical part, the correlation factors of the cations are expressed in terms of the tracer diffusion coefficients or the elementary jump frequencies of the cations and the composition of the solid solution. Furthermore, relations for the vacancy diffusion coefficient and the interdiffusion coefficient are given. In the experimental part, the tracer diffusion coefficient of Co in (Co, Mg)O is determined. In view of experimental results obtained for the analogous system (Co, Ni)O, the diffusion coefficients of magnesium ions and of vacancies are calculated. The latter can be compared with experimental data obtained by relaxation measurements. The fair agreement supports the assumptions made in the theory.