Oxygen diffusion in thin YBa2Cu3O7-δ films studied from isothermal electric resistivity measurements

From isothermal four-point electric resistivity measurements we have determined the chemical diffusion coefficients for the in- and out-diffusion of oxygen in epitaxial c-axis oriented films of YBa2Cu3O7-δ in the temperature range 500-650 K. At constant oxygen pressure we have observed the temporal changes in resistivity, following small steps upwards or downwards in temperature. At 600 K for the in- and out-diffusion of oxygen we found about the same diffusion coefficient Dab = 2 x 10-14 cm2 s-1. The temperature dependence of Dab could be well fitted by an Arrhenius law, yielding the same activation energy EA = 1.1 eV for the in- and out-diffusion. (author)