DIFFUSION OF HYDROGEN IN K1-XLIYTA1-YNBXO3 DOPED CRYSTALS

Based on infrared spectra and protonic conductivity measurements, we p ropose a model of hydrogen ion migration-in K1-yLiyTa1-xNbxO3 doped cr ystals and use it to obtain a theoretical estimate of the diffusion co nstant pre-exponential factor Do that is in reasonable agreement with the experimental result. This model shows that the transition energy o f the second, and higher, overtone(s) of the [OH] vibration can be hig her than the activation energy of hydrogen ion migration. (C) 1996 Ame rican Institute of Physics.