The AC conductivity of tellurite glasses doped with Ho2O3

The AC conductivity of zinc tellurite glasses of composition 80TeO(2)-20 ZnO (mol%) doped with Ho3+ ions (0.01, 0.05 and 0.1 g of Ho ions for 10 g of blank glass), was measured in the temperature range 298-478 K and in the frequency range 0.16-100 kHz. The AC conductivity was found to increase with increasing frequency and to follow the power low sigma(AC) (omega) =A omega(s). The frequency exponent s was found to decrease with increasing temperature. The AC conductivity was also found to increase with increasing temperature. The correlation barrier hopping (CBH) model was found to apply to the AC conductivity data. The AC conductivity and dielectric constant decreased with increasing the holmium, ions content, whereas the dielectric loss increased. This behavior was attributed to the suggestion that the rare earth ions form a quasi-molecular complex with the glass network in oxide glasses. (c) 2005 Elsevier B.V. All rights reserved.