Piezoelectric properties of Ca₃NbGa₃Si ₂O₁₄ single crystal

Langasite-type single crystal Ca₃NbGa₃Si ₂O₁₄ (CNGS) was grown by the Czochralski technique. Dielectric, elastic and piezoelectric constants of CNGS were measured by the resonance-antiresonance method. At room temperature, dielectric constants ε₁₁^T/ε₀ and ε₃₃ ^T/ε₀ were 17.8 and 27.9, respectively. Electromechanical coupling coefficients k₁₂, k₂₅ and k₂₆ were also determined as 10.9, 17.3 and 11.9%, respectively. The measurements were carried out in a temperature range from -30 to 80°C. Temperature coefficients of the dielectric, elastic and piezoelectric constants were obtained. The line-focus-beam and plane-wave ultrasonic material characterization system was employed for measuring bulk acoustic velocities, and longitudinal and transverse wave velocities of 7408.4 m/s and 3136.2 m/s, respectively, in the c-direction uncoupled with piezoelectricity at 23°C were obtained. This was in good agreement with the results determined by the resonance-antiresonance method. The density of CNGS was 4125 kg/m³. All the parameters of the CNGS crystal for bulk and surface acoustic wave applications were determined in this research.