Enhancement of dielectric characteristics in donor doped Aurivillius SrBi2Ta2O9 ferroelectric ceramics

In this study. investigations have been made on the crystal structure, surface morphology, dielectric and electrical properties of tungsten doped SrBi2(WxTa1-x)(2)O-9 (0.0 <= x <= 0.20) ferroelectric ceramics. Dielectric measurements performed as a function of temperature at 1, 10 and 100 kHz show an increase in Curie temperature (T-c) over the composition range of x = 0.05-0.20. W6+ substitution in perovskite-like units results in a sharp dielectric transition at the ferroelectric Curie temperature with the dielectric constant at their respective Curie temperature increasing with tungsten doping. The dielectric loss reduces significantly with tungsten addition. The temperature dependence of ac and de conductivity vis-a-vis tungsten content shows a decrease in conductivity, which is attributed to the suppression of oxygen vacancies. The activation energy calculated from the Arrhenius plots is found to increase with tungsten content. (c) 2006 Elsevier Ltd. All rights reserved.