Temperature dependence of piezoelectric properties of grain-oriented CaBi4Ti4O15 ceramics

Piezoelectric properties of grain-oriented bismuth layer structured compound CaBi4O15 ceramics and their temperature dependencies were studied. The grain-oriented CaBi4Ti4O15 ceramics were fabricated by the templated grain growth method. The highly preferentially (00l) oriented CaBi4Ti4O15 ceramics were obtained and their Lotgering (00l) orientation degree was almost 100%. The electromechanical coupling coefficient of the longitudinal vibration mode (k(33)) was approximately three times as large as that of the nonoriented specimen, and the temperature coefficient of resonant frequency (\f(r) - TC \) was the same as that of the nonoriented specimen. The 24 vibration mode is separated from the 15 vibration mode in the thickness shear vibration of the grain-oriented ceramics. The electromechanical coupling coefficient k(15) of the grain-oriented specimen was twice as large as k(15) of the nonoriented ceramics, while, k(24) was one-third that of k(15) of the nonoriented specimen. The \f(r) - TC \ of the 15 vibration mode of the grain-oriented specimen was half that of the 15 vibration mode in the nonoriented ceramics, and that of the 24 vibration mode of the oriented specimen was much larger than that of the 15 vibration mode in the nonoriented ceramics.