Correlative exploration of structural and dielectric properties with Er2O3 addition in BaO–ZnO–LiF–B2O3 glasses

Abstract Structural properties of a novel family of glasses 10BaO–20ZnO–20LiF-(50-x) B2O3-xEr2O3 where x = 0, 0.1, 0.5, 0.7 and 1.0 mol% were analysed through physical parameters, X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC). Successive Er2O3 doping led to an increase in the glass density, refractive index, molar electronic polarizability and field strength around Er3+ ions. Absence of sharp peaks in the XRD profiles confirmed the amorphous nature. Increase in the number of [BO3] and Non-Bridging Oxygens through FTIR analysis and decrease in the glass transition temperature (Tg) with successive Er2O3 addition validated the structural modification in the network which was then correlated with the dielectric properties of the glasses, evaluated through broadband impedance spectroscopy. Variation of dielectric parameters like dielectric constant, loss, loss tangent, quality factor, modulus, capacitance, conductivity was recorded in 323–673 K and 1 Hz-1 MHz range. An improvement in the dielectric constant was found with the successive addition of Er2O3. High quality factor was observed at 323–523 K and 1 kHz to 1 MHz. ac- (σac) and dc- (σdc) components of electrical conductivity were identified by Jonscher's universal power law. Using Arrhenius relation, high activation energies (>1 eV) were obtained for all the glasses. Cole-Cole plot attributed the relaxation to non-Debye type. From the decreasing values of frequency component (s) in the Jonscher's universal power law with increasing temperature, the conductivity mechanism in the glasses was assigned to Correlated Barrier Hopping model.