title: Nonuniversal features of the ac conductivity in ion conducting glasses
abstract: Recently, Sidebottom [Phys. Rev. Lett. 82, 3653 (1999)] proposed a new scaling approach for the conductivity spectra of ion conducting glasses. This approach is based on the condition that the shape of the spectra is universal. In this Letter, we show that this condition is generally not fulfilled, but that the shape depends on the glass composition. In single alkali glasses, the frequency dependence of the conductivity varies with the alkali oxide content. Furthermore, the mixing of dissimilar alkali ions leads to pronounced changes in the shape of the conductivity spectra.
authors.affiliation: Institut fur Physikalische Chemie, Westfalische Wilhelms-Universitat Munster and Sonderforschungsbereich 458, Schlossplatz 4/7, 48149 Munster, Germany.
authors.initials: B
authors.lastname: Roling
authors.initials: C
authors.lastname: Martiny