Growth and piezoelectric properties of Sr3Ta(Al0.5Ga0.5)3Si2O14 crystals with langasite structure

New piezoelectric crystal Sr
₃
Ta(Al
_0.5
Ga
_0.5
)
₃
Si
₂
O
₁₄
(STAGS) with ordered langasite structure was successfully grown by Czochralski method. The lattice parameters of STAGS were a = 8.269 Å, c = 5.036 Å. The rocking curve evident the crystal quality declined and the diffraction peak shift slightly from top to bottom. Element analysis revealed the Al
³⁺
was not easy to occupy the C site as Ga
³⁺
in crystal. The piezoelectric coefficients d
₁₁
of STAGS was found to be 5.1pC/N and the resistivity was high up to 4.94×10
⁶
Ω·m for top part and 7.08×10
⁶
Ω·cm for bottom part at 700°C, respectively.