Preparation and Characterization of Lanthanum Oxide Doped Barium Strontium Titanate Para Electric Glass Ceramics

(Ba0.3Sr0.7)TiO3-2SiO2-B2O3-K2O based borosilicate glass with and without 0.1 mol % La2O3 was successfully developed by melt-quench method. XRD and FTIR spectra of the glass sample confirms the formation of amorphous structure and presence of stretching and deformation vibrations of B-O-Si linkage and Si–O–Si bridges, respectively. Differential scanning calorimetry (DSC) of glass samples reveals that addition of 0.1 mol % La2O3 elevates the onset of crystallization temperature from ~600°C to ~670°C. Controlled crystallization of the glasses ~750-780°C for 3h leads to the formation of desired perovskite SrBaTiO3 glass-ceramics. SEM-EDS analysis of the undoped glass-ceramic sample shows the formation of micron sized flower-like and needle shaped crystals. However, addition of 0.1 mol % La2O3 modify the crystal structure to blocky precipitates. Results from dielectric measurements suggest that space charge polarization mechanism is likely responsible for the large observed dielectric constant (~700) of the 0.1 mol % La2O3 doped glass ceramics sample at low frequencies.