DIFFUSION OF HYDROGEN DEFECTS IN BATIO3 CERAMICS AND SRTIO3 SINGLE-CRYSTALS

The deuteron diffusion in acceptor-doped barium titanate ceramics is studied as a function of the dopant concentration (0 to 1. 0 mol% Ni) using a thermal desorption technique. The 0. 1 mol% Ni-doped sample shows a diffusion coefficient D equals 290 cm**2 s** minus **1 multiplied by (times) exp( minus 151 kJ mol** minus **1/RT). The dopant concentration has only little influence on the deuteron diffusion rate in the temperature range considered (approx. 850 K to 1150 K). The results are discussed with reference to the diffusion coefficient of oxygen vacancies. In addition, an IR spectroscopic study of the deuteron/ proton exchange in SrTiO//3 single crystals is reported. The hydrogen defect diffusion data obtained by this technique are compared to the results of the thermal desorption study.