Piezoelectric Properties of Sr₂Bi₄Ti₅O₁₈–Ca₂Bi₄Ti₅O₁₈ Solid Solution Ceramics

Piezoelectric properties of Sr ₂ Bi ₄ Ti ₅ O ₁₈ (SBT)–Ca ₂ Bi ₄ Ti ₅ O ₁₈ (CBT) solid solution, that is, Sr_{2(1− x)}Ca_2x Bi ₄ Ti ₅ O ₁₈ [SCBT-x] (0 ≤ x ≤ 1) with m = 5, were investigated. Effects of grain orientation in SCBT system on their piezoelectric properties are also studied using the hot-forging (HF) method. On the ordinarily fired (OF) samples without orientation, electromechanical coupling factor, k _33, and piezoelectric constant, d ₃₃ , of the MnCO ₃ (0.4 wt%) doped SCBT-0 were 0.15 and 26 pC/N, respectively. On the other hand, the HF-SCBT-0 showed relatively high k ₃₃ and d ₃₃ values of 0.29 and 51 pC/N, respectively. Temperature coefficient of the resonance frequency, TC-f _r , in the (33) mode of SCBT-0 (OF) and HF-SCBT-0 were –89.2 ppm/°C and –63.0 ppm/°C, respectively.

Keywords:

• Bismuth layer-structured ferroelectrics
• BLSF
• grain orientation
• electromechanical coupling factor
• mechanical quality factor
• temperature coefficient of resonance frequency

Acknowledgments

This work was partially supported by Grant-in-Aid for Scientific Research (B) (No. 13555176, 15360352) from the Japan Society for the Promotion of Science.

Paper originally presented at AMF-4, Bangalore, India, December 12–15, 2003