Structural characterization of the ac conductivity in Ag ion conducting glasses

The material trends in various silver ion conducting glasses have been studied recently by focusing on the relationship between the first sharp diffraction peak (FSDP) wave number Q, and the fitting parameters of the ac conductivity, precisely the ratio (log A)/n, where A and n represent the pre-exponential factor and the power law exponent of Jonscher’s law, respectively. In the present paper, a model for the FSDP wave number dependence of the ratio (log A)/n has been proposed and a good agreement has been found with the experiments. By using the concept of bond fluctuation in superionic conductors, the results have been successfully explained, leading to the conclusion that the universal aspect of the power law reflects the universal pattern of the potential barrier at intermediate length scales. The result reconfirms that the ion transport in glasses is intimately related with the FSDP wave number.