Electrical transport studies in alkali iron phosphate glasses

The electrical properties of xFe(2)O(3) - (100 - x) Na2P2O5 glasses with x = 0, 6, 12, 18 and 24 mol% have been studied in the temperature range from 323 to 573 K. The dc conductivity was found to decrease as the iron content increases while the activation energy increases with increasing iron content in the glasses. In the high - temperature regime above theta(D)/2(theta(D) is the Debye temperature), the Mott model of small polaron hopping (SPH) between nearest neighbors is consistent with the conductivity data. The electron - phonon interaction coefficient gamma(P) was very large (66.74 - 97.60). The electrical conduction of the glasses was confirmed to be non-adiabatic small polaron hopping. The physical parameters obtained by fitting the experimental results to these models are consistent with glass compositions. (C) 2006 Springer Science + Business Media, Inc.