Thermal, structural and electrical studies of bismuth zinc borate glasses

• Activation energy for dc conductivity decreases with the increase of Bi2O3 content.
• Increase of non-bridging oxygens (NBOs) led to decrease in activation energy.
• DTA and FTIR studies reveal that NBOs increase with the Bi2O3 content.

Bismuth Zinc Borate glasses with compositions xBi2O3–30ZnO–(70 − x)B2O3 (where x = 30, 35, 40 and 45 mol %) have been prepared by melt quenching method. These glasses were characterized by X-ray diffraction (XRD), Differential Thermal Analysis (DTA), Fourier Transform Infrared Spectrometer (FTIR) and Broad Band Dielectric Spectrometer (BDS). DTA and FTIR analysis reveals that Non-Bridging Oxygens (NBOs) increase with increase of bismuth content in the glass. Electrical data have been analyzed in the framework of impedance and modulus formalisms. The activation energy for dc conductivity decreases with increase of bismuth concentration. The imaginary part of modulus spectra has been fitted to non-exponential Kohlrausch–Williams–Watts (KWW) function and the value of the stretched exponent (β) is found to be almost independent of temperature but slightly dependent on composition.

Complex impedance plots of BZB40 sample. The solid lines are the fits to the experimental data.Figure optionsDownload as PowerPoint slide