Calcium Diffusion along High‐Diffusivity Paths in Single‐Crystal MgO

The lattice and dislocation diffusion coefficients for Ca 2+ in single‐crystal MgO have been determined in the temperature range 1743 to 1293 K from the diffusion penetration determined using secondary ion mass spectrometry. The dislocation diffusion coefficients were 4 to 5 orders of magnitude larger than the lattice diffusion coefficients in the same temperature range. The activation energy of Ca 2+ lattice diffusion was comparable to that of ionic conductivity. The diffusion mechanism of Ca 2+ is related to Mg vacancies.