Bridgman growth and characterization of the structure ordered CTGS single crystal

Structural ordered langasite-type piezoelectric crystal Ca₃Ta G a ₃Si₂O₁₄(CTGS) possess excellent high temperature piezoelectric properties. In this work, large size(25mm in diameter and 80mm in length)CTGS single crystalswere grown by using the vertical Bridgman method. High resolution X-ray diffraction technique was applied to characterize the crystal quality, where the as-grown CTGS crystals were found to show low FWHM value, being on the order of<;50", indicating the high quality of the CTGS crystals. In addition, the temperature dependent behaviours for the elastic and piezoelectric properties were investigated from 20°C to 900°C, where piezoelectric coefficient d₁₁(-d₁₂) was found to increase with temperature with variation less than 30%, while the variation of the elastic compliance s₂₂ was obtained to be <;10% over the test temperature range, similar to the CTGS crystals grown by using Czochralski method. All these results indicated that Bridgman method is an alternative to Czochralski method for high quality CTGS crystal growth.