The ac conductivity resulting from ion motion in glasses displays a power-law frequency dependence characterized by an exponent n3. The second are the alkali-metal metaphosphate glasses, MPO3, where M=Li, Na, K, Rb, or Cs. In both glass systems, the conductivity exponent varies with expansion of the phosphate chains which comprise the glass network. In the AgI-doped glasses, n increases with increasing expansion of the network, whereas in the alkali-metal series, n decreases with the expansion. However, when n is considered as a function of the "constriction" of the cation (i.e., the cation size relative to the chain separation), this exponent behaves similarly for both glass systems, decreasing with increasing constriction of the cation. This decrease is proposed to result from a reduction in the coordination of the cation's local conduction space caused by increased constriction.
|Original language||English (US)|
|Number of pages||10|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - 2000|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics