Electro-elastic characterization of Ca3TaGa3Si2O14 crystals for lateral-field-excitation acoustic wave sensing applications

The Ca3TaGa3Si2O14 (CTGS) crystals with ordered structure are promising for piezoelectric sensing applications. In this work, the electro-elastic constants of CTGS crystals were determined taking advantage of impedance and pulse-echo methods. The relative dielectric permittivities ε11T/ε0 and ε33T/ε0 are 17.5 and 21.8, the elastic stiffness constants c11E, c12E, c13E, c14E, c33E, c44E and c66E are 15.63, 7.52, 8.55, 0.05, 22.51, 4.15 and 4.06 × 1010 N/m2, while the piezoelectric coefficients d11 and d14 are 4.17 and −13.7 pC/N, respectively. In addition, the properties of lateral-field-excitation (LFE) acoustic wave were studied, where crystal cut with pure-LFE was designed and LFE acoustic wave prototype was fabricated. The mechanical quality factor Qm for CTGS based pure-LFE device in distilled water was obtained to be 1400, nearly two times that of La3Ga5SiO14 based device, potential for sensing applications in liquid-phase environment.