The serial sectioning technique was used to study the diffusion of 89Sr in optical-grade single crystals. It was suggested that diffusion was due to some degree of Schottky disorder within the temperature range studied. The results for 1000 to 1200C could be described by:

D (cm2/s) = 1.72 x 105 exp[-4.37(eV)/kT]

The large values of the Arrhenius parameters were explained in terms of excess impurity-induced anion vacancies and/or cation diffusion via associated vacancy pairs.

Cation Diffusion in Fluorite Single Crystals. M.Baker, A.Taylor: Journal of Physics and Chemistry of Solids, 1969, 30[4], 1003-7