Enhanced dielectric, ferroelectric and optical properties of lead free (K0.17Na0.83)NbO3 ceramic with WO3 addition

Polycrystalline lead-free ceramics (K0.17Na0.83)NbO3 + x wt.% WO3; (x = 0, 1, 3 and 5) have been synthesized via solid state reaction method. X-ray diffraction pattern at room temperature indicates the formation of pure perovskite phase with monoclinic structure for all samples. Dielectric constant versus temperature measurements shows an increase in dielectric constant with a shift in Curie temperature (TC) toward higher temperature side. Remnant polarization (Pr) is found to be enhanced and reached upto 24 μC/cm2 for x = 5 wt.% WO3 from 12.5 μC/cm2 for pure (K0.17Na0.83)NbO3 ceramic. The value of coercive field (Ec) decreases with increasing wt.% of WO3. From optical band gap study, we found blue shift in the band gap of (K0.17Na0.83)NbO3 with increasing concentration of WO3.