Diffusion coefficient of oxygen in La1.7Sr0.3CuO4-delta

The chemical diffusion coefficient, (D) over tilde, of oxygen in La1.7Sr0.3CuO4-delta in a temperature range of 800 similar to 1000 degrees C was estimated with the analysis of weight relaxation behaviour for the step change of oxygen partial pressure using high temperature gravimetry, The analysis was carried out using numerical approximations of the analytical solution of the diffusion equation, the method of which was optimized in this study. Vacancy diffusion coefficients, D-nu, were also calculated using (D) over tilde and oxygen nonstoichiometry data. Both (D) over tilde and D-nu showed smaller values than those of other conducting oxides with perovskite-family structure and their temperature dependence was Arrehenius type with an activation energy of 1.66 eV. These results are essentially consistent with those for La1.74Sr0.26CuO4-delta reported by Fueki and coworkers.