Dielectric and Piezoelectric Properties of Nonstoichiometric Sr1？xBi2？yTa2O9 and Sr1？xBi2？yNb2O9 Ceramics

Abstract

<TEX>$Sr_{l}$</TEX> <TEX>$\pm$</TEX>x/<TEX>$Bi_{2}$</TEX> <TEX>$\pm$</TEX>y/<TEX>$Ta_2$</TEX> <TEX>$O_{9}$</TEX> and <TEX>$Sr_{l}$</TEX> <TEX>$\pm$</TEX><TEX>$Bi_{x}$</TEX> <TEX>$2\pm$</TEX>y<TEX>$Nb_2$</TEX><TEX>$O_{9}$</TEX> ceramics were prepared by a solid state reaction method. X-ray diffraction analysis indicated that single-phase of Bi-layered perovskite was obtained. According to Sr/Bi content ratio, Curie temperature( <TEX>$T_{c}$</TEX>), electromechanical factor(<TEX>$K_{p}$</TEX> ) and mechanical quality factor(<TEX>$Q_{m}$</TEX> ) were measured. The Curie temperature of SBN(SBT) rose from <TEX>$414^{\circ}C$</TEX>(314<TEX>$^{\circ}C$</TEX>) to <TEX>$494^{\circ}C$</TEX>(426<TEX>$^{\circ}C$</TEX>) when Sr/Bi content ratio was increased. In the case of Sr/Bi content ratio = 0.55/2.3, the maximum value of the mechanical quality factor <TEX>$Q_{m}$</TEX> of SBT and SBN were obtained 3320 and 1010, respectively.