Growth and characterization of a new langasite‐type single crystal Sr 3 NbAl 1.5 Ga 1.5 Si 2 O 14

Single crystals of Sr 3 NbAl 1.5 Ga 1.5 Si 2 O 14 (SNAGS) with langasite structure have been successfully grown by Czochralski method. The X‐ray diffraction (XRD) verified that the as‐grown crystal was isostructural with A 3 BC 3 D 2 O 14 structure and the lattice parameters were calculated as follows: a = 8.242 Å, c = 5.041 Å, V = 296.6 Å 3 . The piezoelectric coefficient d 11 was 5.7pC/N, which was 2.47 times of α‐quartz (d 11 =2.31pC/N). The electric resistivity was up to 3.04×10 6 Ωcm at 700 °C for X‐cut sample. In addition, the transmission spectrum of the SNAGS crystal showed that it had a high transmittance (>80%) in the range of 350‐800 nm and exceeded 90% above 520 nm. These results suggest that the SNAGS crystals have potential applications in high‐temperature piezoelectric sensors and optical techniques. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)