Characterization of high temperature piezoelectric crystals with an ordered langasite structure
Abstract
Piezoelectric single crystals with the ordered langasite structure A3BC3D2O14, including Sr3TaGa3Si2O14, Sr3NbGa3Si2O14, Ca3TaGa3Si2O14, and Ca3TaAl3Si2O14 (CTAS), were studied as a function of temperature, up to 900 °C. The dielectric permittivity ɛ11 and piezoelectric coefficient d11 of the ordered crystals were found to be on the orders of 12-16 and 4-5 pC/N, respectively, slightly lower than langasite (La3Ga5SiO14-LGS) or langanite (La3Ga5.5Nb0.5O14) crystals which possess a disordered structure. The mechanical quality factor Q and electrical resistivity ρ, however, were found to be greatly improved at elevated temperatures ≥500 °C, being one to two orders of magnitude higher, due to cation ordering. Of particular interest is the CTAS crystal, in which, the Ga cations are totally replaced by low cost Al cations. Together with its thermally stable piezoelectric properties and high electrical resistivity, CTAS crystals offer a competitive material for high temperature sensing applications.
- Publication:
-
Journal of Applied Physics
- Pub Date:
- June 2009
- DOI:
- 10.1063/1.3142429
- Bibcode:
- 2009JAP...105k4107Z
- Keywords:
-
- 77.65.-j;
- 77.84.Fa;
- 77.22.Ch;
- 72.80.Sk;
- Piezoelectricity and electromechanical effects;
- KDP- and TGS-type crystals;
- Permittivity;
- Insulators