COMPARISON OF THE OXYGEN DIFFUSION IN Y1BA2CU3OY BULK MATERIALS AND THIN-FILMS

The kinetics of oxygen diffusion was investigated in Y1Ba2Cu3OY, bulk material and laser ablated thin films on MgO. From isothermal annealing experiments in different oxygen partial pressures the diffusion coefficients, activation energies and time-temperature-transformation (TTT) diagrams were determined and discussed in regard to the oxygen content and the different microstructure of the bulk pellets and the thin films. Diffusion coefficients for the oxygen diffusion in the bulk material of between 1.10(-12) and 2.10(-10) cm2/s were determined by thermogravimetric measurements in the temperature range of 300-degrees-C to 700-degrees-C. Within the same temperature region in the laser ablated films (T(c) = 92 K, j(c)(77 K) = 3 . 10(6) A/cm2) diffusion coefficients of between 3 . 10(-15) to 3 .10(-12) cm2/s were obtained by in-situ resistance measurements. In both materials the activation energies for the oxygen diffusion decrease with decreasing oxygen content.