AC conductivity and dielectric properties of SiO2-Na2O-B2O3-Gd2O3 glasses

The present paper studies the dielectric properties and ac conductivity of sodium borosilicate glasses doped with varying concentrations of Gd2O3, while maintaining the SiO2:Na2O:B2O3 ratios constant for all compositions. The samples were prepared using rapid quenching method. Their dielectric and electrical properties were measured in the frequency range (10(2)-10(6) Hz) and temperature range (298-523 K). Experimental results showed that all dielectric and electrical properties are dominated by mole% of Gd2O3. The decrease and increase in these properties were found to be due to formation of short range ordered structure and non-bridging oxygen, respectively. Different models were suggested to describe the conduction mechanism of the investigated compositions based on mole% of Gd2O3. Correlated barrier hopping model (CBH) was suggested to describe the conduction mechanism of 0-2.52 mole% Gd2O3 doped - samples. While, overlapping large polaron tunneling (OLPT) model was applied to describe conductivity of 2.83 mole% Gd2O3 doped sample. Interestingly, an inverse - OLPT model was suggested to describe the conduction mechanism of composition doped with 3.13 mole% of Gd2O3. (C) 2013 Elsevier B.V. All rights reserved.