Growth and characterization of 6 inch Ca3Ta(Ga0.25Al0.75)3Si2O14 for high-temperature piezoelectric applications

Abstract

6 in. Ca₃Ta(Ga_0.25Al_0.75)₃Si₂O₁₄ (CTGAS) crystals have been successfully grown with the Czochralski technique. The growth habits, formation mechanisms of phase separation and inclusions in the core region for the as-grown crystals were analyzed in detail. The full width at half-maximum (FWHM) values of rocking curves were found to be 18.2–18.8′′. The complete sets of dielectric, elastic and piezoelectric coefficients for CTGAS were characterized with the resonance method at room temperature, and the piezoelectric coefficients d₁₁ and d₁₄ and electromechanical coupling factors k₁₂ and k₂₆ were measured to be 4.63 pC N⁻¹, −5.93 pC N⁻¹, 13.96%, and 4.43%, respectively. The temperature characteristics of the electrical properties for CTGAS were measured in the range from 70–840 °C. At 800 °C, the electrical resistivity was determined to be 2.5 × 10⁶ Ω cm and CTGAS showed high thermal stability of piezoelectric and electromechanical properties.