Temperature dependence of electro-elastic properties of yttrium calcium oxyborate single crystlals

High temperature piezoelectric crystals, YCa₄O(BO₃)₃ (YCOB) possess relatively high piezoelectric activities (d_eff = ~7.8pC/N, k_eff= ~19%) and no phase transition prior to the melting point (~1500°C), indicating the potential use for high temperature sensing. In this work, growth of YCOB single crystals by using Czochralski (Cz) method was introduced and the temperature dependence of electro-elastic properties was investigated from 20 to 950°C, where the resonance frequencies relating to elastic compliances _sE₃₃ and _sE₅₅, were found to shift linearly with increasing temperature, with relatively large first order temperature coefficient being on the order of ~94ppm/°C. Of particular significance is that the lateral mode of (XY) and (XZ) crystal cuts were found not only possess relatively high electromechanical coupling factor (k_eff= ~15%) and piezoelectric coefficient (d_eff = ~4 pC/N), but also the temperature independence of electromechanical properties, demonstrating YCOB a good candidate for high temperature piezoelectric sensing.