Role of WO3 nanoparticles in electrical and dielectric properties of BaTiO3-SrTiO3 ceramics

Abstract

(BaTiO3-SrTiO3)/(WO3)(x) ceramics with x = 0 up to 5% were synthesized using solid-state reaction via high-energy ballf milling technique. Various characterization techniques were used including X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform-infrared spectroscopy (FT-IR), and UV-visible diffuse reflectance (DR) spectrophotometer. Structural analysis via XRD indicates the formation of two separate phases of SrTiO3 (STO) and BaTiO3 (BTO) having both cubic structures. The presence of BaWO4 as impurity was detected for higher concentration. SEM observations show a reduction in the average grains size with increasing WO3 addition. In comparison with free-added ceramic, the optical band gap energy (E-g) shows a slight increase with WO3 addition. Contextual investigations on the electrical and dielectric properties of various WO3 added to BTO-STO ceramics have been used to evaluate conductivity (sigma), dielectric constant and loss (epsilon r ' and epsilon r ''), and dissipation factor (tan delta) against both frequency and dc bias voltages. Generally, both sigma and epsilon r '' correspond to the tendency of the power law to frequency. However, dc bias has been noticed to be lesser affecting the conduction mechanisms, which has a small variation for various WO3 addition ratios. In addition, the dissipation factor was found to be highly dependent on both the addition ratio and the frequency as well as dc bias applied.