DC conductivity of rare earth ions doped vanado-tellurite glasses

Abstract

Two novel sets of vanado-tellurite glasses doped with rare earth ions (La2O and CeO2) have been investigated for density and dc electrical conductivity in the temperature range 300-500 K. The conductivity data has been analyzed in the light of Mott's small polaron hopping (SPH), variable range hopping (VRH) and Greave's VRH models. The electrical conduction was confirmed to be due to non-adiabatic small polaron hopping in nature. High temperature conductivity behavior was found to be in agreement with Mott's SPH model. The low temperature conductivity behaved as per Mott's VRH model. Various physical and polaronic parameters, such as radius, bandwidth and coupling constant, have been determined and discussed. © 2008 Elsevier B.V. All rights reserved.