Oxygen ion diffusion in single crystal SrTiO3

The oxygen ion self-diffusion coefficient has been determined for single crystal SrTiO3 between 825° and 1525°C. The rate of exchange between oxygen gas enriched with the stable isotope, O18, and solid single crystal plates and spheres was measured. Diffusion rates for annealed crystals were independent of oxygen pressure between 15 and 570 torr at 1400°C and probably at lower temperatures. Below 1200°C, oxygen ion diffusion depends on prior heat treatment and dislocation density, although a quantitative relationship was not determined. For a dislocation density of ∼1·4 × 106/cm2, the temperature dependence of the diffusion coefficient can be represented by D = 1·6 × 10−7 exp(−15·5 ± 2·0 kcal/RT) between 825° and 1200°C. For a dislocation density of ∼6·6 × 105/cm2, the diffusion coefficient can be represented by D = 1·2 × 10−5 exp(−29·3 ± 3·0 kcal/RT)between 850° and 1525°C.