In situ monitoring and quantitative analysis of oxygen diffusion through Schottky-barriers in SrTiO3 bicrystals

The blocking effect of boundaries in SrTiO3 bicrystals on the chemical diff usion of oxygen is monitored in situ. The optical technique that is applied allows precise recording of spatial profiles as a function of time. The lo w symmetrical boundary (near Sigma 13) shows a pronounced chemical resistan ce reflected by a distinct jump of the diffusion profiles, while the highly symmetrical Sigma 3 boundary exhibits no measurable influence. The effects can be quantitatively explained by Schottky barriers and the diffusion pro files precisely modeled with the space-charge potential as the only unknown parameter. The space-charge potentials are in good agreement with the valu es derived from impedance analysis. (C) 1999 The Electrochemical Society. S 1099-0062(98)12-024-7. All rights reserved.