The T-ion conductivities of Ba(Ce0.9Yb0.1)O2.95 and Sr(Zr0.9Yb0.1)O2.95 were measured by means of alternating-current impedance analysis. The impedance plots were found to consist of clearly resolved bulk and grain-boundary arcs at temperatures ranging from 50 to 350C. An isotope effect was easily identified. A decrease in the bulk conductivity with increasing isotopic mass was attributed to an increase in the activation energy for conduction; together with a decrease in the pre-exponential factor. Because the concentration of the H, D or T was expected to remain fairly constant at temperatures below 350C, the overall increase in activation energy was attributed directly to an increase in the activation energy for isotope mobility.

Tritium Conductivity and Isotope Effect in Proton-Conducting Perovskites. R.Mukundan, E.L.Brosha, S.A.Birdsell, A.L.Costello, F.H.Garzon, R.S.Willms: Journal of the Electrochemical Society, 1999, 146[6], 2184-7