Ferroelectric and piezoelectric properties of tungsten substituted SrBi2Ta2O9 ferroelectric ceramics

Tungsten substituted samples of compositions SrBi₂(W_xTa_1−x)₂O₉ (x = 0.0, 0.025, 0.050, 0.075, 0.10 and 0.20) were synthesized by solid-state reaction method and studied for their microstructural, electrical conductivity, ferroelectric and piezoelectric properties. The X-ray diffractograms confirm the formation of single phase layered perovskite structure in the samples with x up to 0.05. The temperature dependence of dc conductivity vis-à-vis tungsten content shows a decrease in conductivity, which is attributed to the suppression of oxygen vacancies. The ferroelectric and piezoelectric studies of the W-substituted SBT ceramics show that the remanent polarization and d₃₃ values increases with increasing concentration of tungsten up to x ≤ 0.05. Such compositions with low conductivity and high P_r values should be excellent materials for highly stable ferroelectric memory devices.