Growth and piezoelectric properties of Al-substituted langasite-type La3Nb0.5Ga5.5O14 crystals

The influences of aluminum substitution for gallium in the langasite-type La3Nb0.5Ga5.5O14 (LNG) crystals on their growth and electric properties were investigated. Al-substituted LNG (La3Nb0.5Ga5.5−xAlxO14; LNGAx) single crystals up to the solubility limit x = 0.2 have been grown by the conventional Czochralski technique. The electric properties of the LNGAx crystals were investigated and compared to those of LNG. With Al substitution, the piezoelectric constants, d11 and d14, were slightly higher. The LNGAx crystals showed a temperature dependence of d11 similar to that of the LNG crystal.