Experimental study of copper diffusion in YBa2Cu3O7–x polycrystals
Abstract
The self-diffusion of copper in YBa2Cu3O7–x ceramics has been studied using sputtered neutrals mass spectrometry with isotopic marking. Diffusion profiles were formed by the annealing of 63CuO thin films deposited on YBa2Cu3O7–x polycrystal substrates. The effective diffusion coefficient was calculated by an error-function approach. The parameters of the temperature dependence were found to be D0=(2 ± 0.2)× 10–1 cm2 s–1 and Ea= 240 ± 9 kJ mol–1 in the temperature range 730–880 °C. The application of Fisher's grain-boundary diffusion model made it possible to separate contributions of volume and boundary diffusion. The dependence of the copper diffusion coefficient in YBa2Cu3O7–x on P(O2) was investigated.