Ferroelectric and Piezoelectric Properties of Strontium Bismuth Tantalate Ceramics

摘要

The ferroelectric and piezoelectric properties of strontium bismuth tantalate Sr_xBi_yTa_2O_9 (Sr_xBi_yT) ceramics were investigated. Well developed P(polarization)- E(electric field) hysteresis loops were observed for all samples except for the Sr_(1.0)Bi_yT(y >2) ceramics. A large remanent polarization (2P_r=26 μC/cm~2) was observed for the Sr_(0.8)Bi_(2.15)T ceramics sintered at 1150℃. For the Sr_(0.8)Bi_(2.2)T ceramics, the determined electromechanical coupling factor (k_p = 9.7%) and mechanical quality factor (Q_m = 4500) with a radial-extensional mode were obtained. Those of the stoichiometric SBT ceramics are k_p - 4.0%. The cation vacancy and/or Bi incorporation into the Sr site of SrBi_2Ta_2O_9 were effective for enhancement of the electromechanical coefficients.