Electrical conductivity of silver bismuth borate tellurite glasses

The AC electrical conductivity of (Ag2O)(x)(Bi2O3)(30)(B2O3)(60-x)(TeO2)(10) glass (x = 0, 2, 4, 5, 10, 15 and 20) were measured at different temperatures and frequencies. The results obtained indicated that glasses containing silver < 5 mol% have values nearly approximately equal to AC electrical conductivity. A slight decrease was observed with increasing Ag2O concentration up to 4 mol%. However, the AC electrical conductivity values increase with increasing silver content, i.e. >= 5 mol%. The AC electrical conductivity values, increased with increasing frequency and follow the power law, sigma(AC) = A omega(s). The frequency exponent s was found to be dependent on frequency and temperature. The s values tended to increase to unity as the temperature decreased. Such results suggest that the correlated barrier-hopping (CBH) model is appropriate for explaining the AC electrical conductivity in these glasses. A pronounced increase in the dielectric loss values was observed with increasing silver content. These reflect the effect of Ag+ ions charge carriers on the electrical conductivity of such glasses. (C) 2008 Elsevier B.V. All rights reserved.