Effect of substituting iron on structural, thermal and dielectric properties of lithium borate glasses

Abstract Glasses with composition x Fe 2 O 3 ·(30 − x )Li 2 O·70B 2 O 3 ( x = 0, 2, 5, 7 and 10 mol%) were prepared via melt-quenching technique and their physical, thermal and dielectric properties are discussed. XRD was carried out to confirm the amorphous nature of prepared glasses. Density ( ρ ) and molar volume ( V m ) were found to increase with increase in Fe 2 O 3 content. Infrared absorption spectra depicted that Fe 2 O 3 is acting as a network modifier. DTA has been carried out to determine glass transition temperature ( T g ) and crystallization temperature ( T x ). Electrical properties have been studied using impedance spectroscopy and dc conductivity. The dc conductivity decreases and activation energy increases on replacing Li + ions with Fe 3+ . The impedance measurements reveal that the total conductivity obeys Jonscher’s power law. Study of the equivalent circuit analysis up to a temperature of 523 K shows a significant change in the equivalent circuitry with change in temperature and composition.