SCALING BEHAVIOR IN THE FREQUENCY-DEPENDENT CONDUCTIVITY OF MIXED-ALKALI GLASSES

The frequency dependent conductivity of xLiF-(80 - x)KF-20Al(PO3)(3) m ixed alkali glasses has been studied at 323 K less than or equal to T less than or equal to 523 K and over a frequency range 20 Hz less than or equal to v less than or equal to 1 MHz, The data have been analyze d assuming a power-law for the frequency dependence of the conductivit y. We demonstrate that while the individual compositions exhibit tempe rature independent scaling of the ac conductivity, the composition dep endent ac conductivity can be explained only using two scaling functio ns, one each for the dominant K+ and Li+ cation regions on either side of the minimum in the ac/dc conductivity of the mixed alkali glasses. This is consistent with the dynamic structure model. It is proposed t hat the ion dynamics in mixed mobile ion glasses may be universally ex plained with two scaling functions. (C) 1998 Elsevier Science B.V. All rights reserved.