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

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 (T_g) 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- (σ_ac) and dc- (σ_dc) 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.