ISOTOPE EFFECT OF PROTONIC CONDUCTIVITY IN LINBO3

The electrical DC conductivity a of LiNbCO3: H,D was studied as a function of temperature, electric field and proton/deuteron dopant concentration. The conductivity follows linearly the hydrogen content over two orders of magnitude. Independent holographic measurements on the same samples confirm these results in the temperature range 75 - 150 °C. The activation energy for protonic and deuteronic migration turns out to be equal, Eact, H = Eact, D= 1.23 ± 0.04eV. The isotope effect of the pre-exponential factor reflects the mass dependence of the attempt frequency and shows the protons to be the migrating species rather than hydroxyl ions. © 1991, Taylor & Francis Group, LLC. All rights reserved.