Diffusion of barium ions in the Ba3-3xLa2x?x(VO4)2 solid solution

Diffusion coefficients for 133Ba, 90Sr, and 45Ca radionuclides in the solid solution Ba3-3xLa2x?x(VO4)2 (x = 0, 0.05, 0.1, 0.15) are measured in the temperature range 800 to 1000°C using the layer-by-layer radiometric analysis. It is established that Dca* ? DSr? > DBa*. Increasing the concentration of vacancies ? in the barium sublattice leads to an increase in the diffusion coefficients of the alkaline-earth metal cations. The activation energies for the radionuclide diffusion are determined; their values (?1.1 eV) are close to the activation energy for ionic conduction. Cations M2+ are shown to migrate via the positions of Ba(2). © 1999 MAHK "Hayka/Interperiodica Publishing"