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

Abstract

6 in. Ca3Ta(Ga0.25Al0.75)3Si2O14 (CTGAS) crystal has been successfully grown by Czochralski technique. The growth habits, formation mechanisms of phase separation and inclusions in the core region for 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 by resonance method at room temperature, and the piezoelectric coefficients d11, d14 and electromechanical coupling factors k12, k26 were measured to be on the order of 4.63 pC/N, -5.93 pC/N and 13.96%, 4.43%, respectively. The temperature characteristics of electrical properties for CTGAS were measured in the range from 70 – 840 oC. At 800 oC, the electrical resistivity was determined to be 2.5×106 Ω·cm. and CTGAS showed high thermal stability of piezoelectric, electromechanical properties.