Composition Dependence of the Dispersive Nature of the ac Conductivity in Ionic Conductors Gd2Ti2-yZryO7 and Li0.5-xNaxLa0.5TiO3
J. García-Barriocanal; K.J. Moreno; A.F. Fuentes; J. Santamaría; C. León. Composition Dependence of the Dispersive Nature of the ac Conductivity in Ionic Conductors Gd2Ti2-yZryO7 and Li0.5-xNaxLa0.5TiO3. Journal of Non-Crystalline Solids (ISSN: 0022-3093). 2006, Vol. 352, p. 5141-2006.
We present Admittance Spectroscopy measurements on two different ionically conducting materials, Gd2Ti2-yZryO7 and Li0.5-xNaxLa0.5TiO3. Electrical relaxation data have been found to be well described by stretched exponential functions. In Gd2Ti2-yZryO7 the concentration of mobile ions in the whole series is very low, from 1% to 0.02 %, and we find that by strongly decreasing the density of mobile ions the value of the exponent n shows a significant decrease form 0.44+0.01 to 0.16+0.01. In Li0.5-xNaxLa0.5TiO3 we have investigated changes in ion dynamics when approaching the percolation threshold for lithium diffusion by increasing the number of immoble sodium ions, and found that the exponent n increases towards a value of 0.81+0.01 as the mobility of lithium ions becomes more and more constrained close to the percolation threshold. Both results are discussed in terms of the importance of ion-ion correlations in the dispersive behavior of the electrical conductivity
We present Admittance Spectroscopy measurements on two different ionically conducting materials, Gd2Ti2-yZryO7 and Li0.5-xNaxLa0.5TiO3. Electrical relaxation data have been found to be well described by stretched exponential functions. In Gd2Ti2-yZryO7 the concentration of mobile ions in the whole series is very low, from 1% to 0.02 %, and we find that by strongly decreasing the density of mobile ions the value of the exponent n shows a significant decrease form 0.44+0.01 to 0.16+0.01. In Li0.5-xNaxLa0.5TiO3 we have investigated changes in ion dynamics when approaching the percolation threshold for lithium diffusion by increasing the number of immoble sodium ions, and found that the exponent n increases towards a value of 0.81+0.01 as the mobility of lithium ions becomes more and more constrained close to the percolation threshold. Both results are discussed in terms of the importance of ion-ion correlations in the dispersive behavior of the electrical conductivity