Optically measured diffusion constants of oxygen vacancies in MgO

We report the estimation of diffusion constants for oxygen vacancies in MgO based on optical absorption spectra. MEO single crystals were annealed in a reducing atmosphere (H-2 + Ar) to create oxygen vacancies and the samples were annealed in an oxidizing atmosphere (O-2 + Ar) to annihilate them. Fe 3+ impurities in the MgO samples were utilized to monitor the degree of red uction or oxidation of the samples during the annealing cycle. An activatio n energy of 3.08 eV for the diffusion of oxygen Vacancies (F-centres) in Mg O was obtained, based on the absorption measurements of Fe3+ band.