Polaron transport studies in La2O-V2O5-P2O5 glasses

Abstract

The glass transition temperature and electrical conductivity in the temperature range 325 K to 525 K have been investigated in a set of La2O doped vanado-phosphate glasses. The measured variation of density and glass transition temperature with La2O content revealed that glass network becomes continuously loose packed with increasing La2O content. Conductivity variation with La2O revealed the contribution of lanthanum ions to the total conductivity. Temperature behavior of conductivity has been explained using Mott's small polaron and variable range hopping models. Various physical and polaron hopping parameters such as, activation energy, polaron hopping energy, polaron radius, effective dielectric constant, polaron bandwidth, electron-phonon coupling constant, hopping site energy and variable range hopping distance have been determined. (C) 2011 Elsevier Masson SAS. All rights reserved.