DC ELECTRICAL-CONDUCTIVITY OF TELLURITE PHOSPHATE-GLASSES

The dc electrical conductivity of the ternary glasses [81 mol, TeO2-19 mol P2O5]0.95 [R(n)O(m)]0.05 (R = La, Ce, Pr, Nd, Sm, and Yb) have been measured in the temperature range 50-300-degrees-C. The electrical conductivity data have been examined and discussed on the basis of small polaron hopping conduction theory for the purpose of determining why rare earth containing tellurite glasses show lower electrical conductivity than the undoped glass. The values of the activation energies were in the range 0.84-1.04 eV depending upon the kind of the rare-earth ion. It is concluded that the lower dc electrical conductivity of these rare earth containing tellurite phosphate glasses is predominantly due to a higher activation energy.