Ionic Transport in Oxide Glasses and Frequency Dependence of Conductivity

Abstract

Current models attribute the power law frequency dependence of ionic conductivity in oxide glasses alternatively to structural disorder or to interactions between moving ions. To distinguish between the influence of disorder and of interaction the frequency dependence of conductivity was investigated for three different series of glasses that have been selected according to special considerations on network structure and bonding of alkali ions. It was shown that the frequency response is independent of alkali concentration and structure. This result is discussed in terms of Coulomb interactions between mobile charged point defects and favours the jump relaxation model of Funke.

Impedance and Raman Spectroscopic Studies on La-modified BLSF Ceramics

“…1(a) as dotted line) at the 1 Hz frequency. Kahnt et al [22] hypothetically predicted that the characteristic frequency (f p and fq) can be approximated in region I and II respectively in the plot. This nature was attributed to the disappearance of the long-range polar order, as pointed out in our earlier paper [25].…”

“…3) is generally attributed to either KWW or other type of relaxation and/or of non-Debye type [17,18]. Apart from this, the size and shape of the asymmetric semicircles (based on the grain and grain boundary contribution) suggests that the heterogeneous nature or migration of vacancies or diffusive and sub-diffusive nature of the mobile charges in non-homogeneous potential environments [21][22][23][24]. log Z" vs. log Z' plots (inset Fig.…”

Scaling and Universality of ac Conduction in Disordered Solids

“…(1), which we shall refer to as "Taylor-Isard scaling," has been used in several different contexts. For instance, Taylor-Isard scaling was used by Scher and Lax in 1973 in their famous papers introducing the continuous time random walk approximation [20], by Summerfield and coworkers in 1985 for amorphous semiconductors [21,22], by van Staveren and coworkers in 1991 for metal-cluster compounds [23], and by Kahnt the same year for ionic glasses [24].…”

Solid State Ionics: from Michael Faraday to green energy—the European dimension

“…They often made their spectra collapse into one, as in figure 28, by means of Summerfield scaling [147], which is the most frequent case of time–temperature superposition of conductivity spectra [212–214]. In the meantime, however, it has become apparent that Jonscher's power-law approach is at variance with both experiment and theory [215, 216].…”

“…In these materials, the charge carriers are alkali ions in their hydrated state. Apart from the usual time–temperature superposition principle [212–214], the authors also detected a corresponding time–humidity superposition principle [277, 278], with the dc conductivity and the onset frequency of the dispersion depending exponentially on relative humidity.…”