Ionic-polaronic behavior in CeO2-PbO-B2O3 glasses

Two glass families with compositions xCeO2-(40−x)PbO-60B2O3 and xCeO2-(50-x)PbO-50B2O3 were prepared and studied. DC conductivity measurements of these glasses show that there is a minimum in both the conductivity at 673 K and the pre-exponential factor at 5 mol% CeO2. The conductivity behavior was attributed to the discontinuity of percolation paths for polarons and cations not to the interactions between them. The conductivity minimum is generated by the “crossover” of the two conductivity curves; the ionic curve and the polaronic one. The ion polaron effect is no longer valid. The activation energies for glasses investigated containing CeO2>5 mol% are in the range of these for polaronic conduction. Density measurements show that the content of PbO in glasses is the dominant factor that affects the density.