Lattice engineering by Sr-substitution leads to high piezoelectric performance of (SrxCa1-x)3TaAl3Si2O14 single crystals

In this work the partial substitution of Ca by Sr in the known langasite single crystal Ca3TaAl3Si2O14 is investigated from the point of view of crystal growth in order to improve the piezoelectric properties. For it, a (SrxCa1-x)(3)TaAl3Si2O14 (SCTAS) single crystal with x = 0.25 was grown by the Czochralski method. The grown crystal was strongly faceted, highly transparent, and of a high crystalline quality, as indicated by a full width at half maximum of the X-ray rocking curve as small as 31 arcsec. On the other hand, the crystal exhibited a high resistivity, with a value over 10(10) Omega cm at 400 degrees C. Temperature dependent piezoelectric measurements confirmed the effective enhancement of the d(11) piezoelectric coefficient at any temperature, while maintaining the dielectric loss below 1% up to 600 degrees C. Therefore, SCTAS exhibits superior properties compared with other piezoelectric materials for high temperature applications. (C) 2020 Elsevier B.V. All rights reserved.