Department of Physics, Queen's University, Kingston, Ontario, Canada K7L 3N6
Abstract:
Glasses of composition 65 mol% LiNbO3:: 35 mol% SiO2 have been shown to be Li+ ion conductors with a conductivity at 200°C > 1 × 10?5 (η cm)?1 and an activation energy of 0.54 eV. The addition of approximately 0.1 mol% Fe2O3 leads to an enhancement of conductivity to ≈10?3 (η cm)?1 at 200°C and an activation energy of 0.67 eV. The effect of Fe is shown to be in the control of microstructure in the glass, with Fe2O3 concentrations < 1 mol% acting as a grain growth inhibitors and larger concentrations acting as a nucleating agents. A model for this process based on the expected stoichiometry of the melt and the effect of Fe2+ and Fe3+ in charge compensation is in excellent agreement with experimental data from electron spin resonance.