Effect of microwave sintering on the structural, optical and electrical properties of BaTiO3 nanoparticles

BaTiO₃ nanoparticles were prepared by high energy ball milling and subjected to conventional and microwave post sintering at 1,000 °C. From the powder X-ray diffraction results, the synthesized material exhibits strong tetragonality with large c/a ratio. Scanning electron microscope results show the formation of tetragonal shaped BaTiO₃ crystals in the nanometer scale and a significant reduction in the particle size for the microwave sintered sample. The reduced d-spacing of 1.741 Å with high crystallinity for the microwave sintered material is revealed by high resolution transmission electron microscopy analysis. Ultraviolet–visible spectroscopy studies confirm the higher optical band gap (E_g) of 4.157 eV for the microwave sintered sample. Microwave sintered sample shows a very high dielectric constant of ε_r = 4,445 with a low dielectric loss as tan δ = 0.0961. Microwave sintered sample exhibit a high polarization maximum of 73 μC/mm² with reduced coercivity to be 0.293 kV/mm.