TRANSPORT IN OXIDESNew investigation of oxygen self-diffusion in Cu2O

New measurements of oxygen self-diffusion coefficients in Cu2O have been performed on single crystals under two oxygen partial pressures (4.6 x 10-4 atm and 0.26 atm) in the stability domain. The stable isotope 18O has been used as a tracer. It has been introduced by a thin film method or by annealing under a constant 18O pressure. The diffusion profiles have been measured by secondary ion mass spectrometry. They obey quite well the solutions of Fick's equation. The results can be represented by : D (cm2 .s-1) = 3 x 10-3 p0,4 O2 exp - 1,55 (eV)/ kT. The defect responsible for the oxygen migration corresponding to the above oxygen partial pressure dependence is the singly charged oxygen interstitial O'i.