Synthesis and characterization of Barium and Strontium doped Sodium Bismuth Titanate

Abstract

This study investigates (Na0.5Bi0.5)1-(x+y)BaxSryTiO3 (NB-BST) ceramics synthesized via the solid-state reaction method. Varied compositions were sintered at 950°C, 1000°C, and 1050°C, influencing average grain sizes (227.20 nm to 481.15 nm). X-ray diffraction affirmed crystal structures. Barium and Strontium doping induced structural transitions from orthorhombic to tetragonal and cubic phases, evidenced by Rietveld analysis. Polarization-Electric Field (P-E) loops exhibited exhibit lossy and dielectric behaviors, revealing temperature-dependent trends. In current-voltage (I-V) characteristics, significant current at lower electric fields, saturating at higher fields, suggests balanced electron and hole conduction. Dielectric measurements illustrate a frequency-dependent increase in dielectric constant at lower frequencies and a decrease at higher frequencies, with loss tangents showing an increasing trend. (Na0.5Bi0.5)1-(x+y)BaxSryTiO3 (NB-BST) ceramics reveals diverse bandgap energies, such as for x=0.6, and y=0, 0.05, 0.10, 0.15, 0.20, the indirect and direct bandgap energies range from 2.84 eV to 3.23 eV. Similarly, at y=0.15, and x=0.30, 0.40, 0.50, 0.60, the bandgap energies vary from 2.84 eV to 3.22 eV, providing a comprehensive understanding of the optical behavior under different compositional and thermal conditions. This comprehensive analysis contributes to the development of lead-free materials, highlighting the impact of dopants on NBT-based ceramics for diverse applications.