Zirconia assisted crystallization of ferroelectric BaBi2Nb2O9 based glass-ceramics: Kinetics, optical and dielectrical properties

Abstract

Crystallization of ferroelectric BaBi2Nb2O9 (BBN) based glass-ceramics (GCs) doped with different amounts of zirconia (ZrO2) as nucleating agent are carried out via the synthesis of base glasses through melt quenching technique followed by temperature controlled crystallization. For the first time, transparent BBN based GCs have been synthesized with ZrO2 promoting bulk nucleation and facilitating evolution of BBN nanocrystals, which was otherwise difficult in the undoped glass. Non-isothermal DSC studies and several trial heat-treatments facilitated in determining the crystallization temperature of 630 °C, at which controlled rate of crystallization was feasible and crystallite size could be controlled in nanometric scale. Comparative crystallization kinetics studies along with XRD and TEM analyses elucidated the role of ZrO2 as nucleating agent in crystallization of the BBN GCs. The refractive index (RI) of the GCs has been increased compared to the corresponding base glasses and found in the range of 1.833–1.854. When ceramized for 30 h, the dielectric constant of the undoped GC has been found to be 131.3 which have been increased enormously to 301 for the 5 mol% ZrO2 doped GC. A maximum polarization of 2.4 μC/cm2 and recoverable energy storage density of 0.014 J/cm3 has been obtained at 150 °C for the 5 mol% ZrO2 doped 30 h heat-treated GC.