THE OXYGEN PERMEATION THROUGH YBA2CU3O6+X

The ionic conductivity of oxygen was studied in the dense ceramic YBa2Cu3O6+x using the oxygen permeation measurements. The temperature interval of measurements was 600-850-degrees-C and the limits of the partial pressure of oxygen were 0.06-1.00 atm. The method was based on the direct determination of the steady flow of oxygen through the specimen in the conditions of constant temperature with a small gradient of oxygen chemical potential along the sample. The oxygen diffusion coefficient was calculated. The activation energy (U) of the oxygen conductivity (diffusion coefficient) was determined in the interval 0.35 < x < 0.6. The dependence of the activation energy on the oxygen content in the tetragonal phase, U=2.80-1.45x (eV), was found. This dependence was explained by the interaction of the mobile oxygen ions.