The diffusion of barium in magnesium oxide

Abstract

Measurements of the diffusion of Ba in single crystal MgO indicate that dislocations can have a strong influence on diffusion coefficients in the temperature range 1000°c-1700°C. Dislocation densities calculated from these coefficients agree with values obtained from photomicrographs. The equations for lattice diffusion and dislocation-influenced diffusion, respectively, are: and where k is Boltzmann's constant in ev/°K and T is the absolute temperature. The bearing of this result on a previously postulated correlation between the activation energy and the ratio of the radius to the electronic polarizability of the diffusing ion is discussed.