Radiotracer and conductivity measurements were used to study the movement of cation vacancies, anion vacancies and vacancy pairs in pure and Sr-doped single crystals. The self-diffusivity of Na+ in extrinsic crystals which were doped with 2.7 x 10-5 Sr2+ could be described by:

D (cm2/s) = 3.53 x 10-6 exp[-0.72(eV)/kT]

In the case of intrinsic crystals, the data could be described by:

D (cm2/s) = 3.32 x 101 exp[-1.98(eV)/kT]

F.Bénière, M.Bénière, M.J.Chemla: Journal of the Physics and Chemistry of Solids, 1970, 31[6], 1205-20

The best linear fits to the solute diffusion data ([382] to [383], [391] to [397], [403] to [405]) yield:

Cs: Ln[Do] = 0.29E – 9.9 (R2 = 0.73); Na: Ln[Do] = 0.57E – 22.4 (R2 = 0.99);

Sr: Ln[Do] = 0.55E – 20.5 (R2 = 0.51)