Electrical and dielectrical properties of SiO2–Li2O–Nb2O5 glass and glass-ceramics obtained by thermoelectric treatments

The electrical and dielectrical properties of the glass and glass-ceramics with the 60SiO2–30Li2O–10Nb2O5 (mole%) composition, containing LiNbO3 crystallites, were studied. The dc electric conductivity (σdc) and dc activation energy (Ea(dc)) decreases with the rise of the heat-treatment (HT) temperature and with the increase of the amplitude of the applied electric field. The highest dielectric constant, 48.19, was observed in the 650HT sample. The dielectrical properties were discussed through a three serial capacitor model, two related with the sample surfaces and one with the bulk material, showing that the bulk has the major contribution for the dielectrical characteristics. A resistance in parallel with a constant phase element (CPE) is the best equivalent circuit that describes the dielectrical behavior. The obtained results reflect the important role carried out by the treatment temperature and the applied electric field in the electrical and dielectrical properties of the glass.