Piezoelectric properties of (Sr_0.2Ca_0.8)₃TaGa₃Si_{2O14 and Ca3TaGa3Si2O14 single crystals grown via vertical Bridgman method}

CTGS crystals are widely used in the field of high-temperature piezoelectricity because of their excellent piezoelectric properties. In this paper, the Ca2+ lattice of CTGS crystals is replaced by Sr2+ with a larger radius to improve their piezoelectric properties. (Sr0.2Ca0.8)(3)TaGa3Si2O14 and Ca3TaGa3Si2O14 single crystals with a diameter of 25 mm were grown using the vertical Bridgman method. The full width at half maximum (FWHM) of X-ray rocking curves of SCTGS and CTGS crystals are 57.6 '' and 22.3 '', respectively. It was found that the thermal properties of SCTGS crystals, such as specific heat, thermal diffusion and thermal conduction, are slightly lower than those of CTGS crystals. At room temperature, the dielectric permittivity epsilon(T)(11) increased from 18.59 to 18.78, and the piezoelectric coefficient d(11) also increased from 4.22 pC N-1 to 4.54 pC N-1. The electrical resistivities of the X-cut plates of SCTGS and CTGS crystals are approximately 3.78 x 10(7) Omega cm and 2.40 x 10(7) Omega cm at 800 degrees C, respectively. Therefore, SCTGS will be a promising candidate piezoelectric material in the field of high-temperature sensing.