Elastic, piezoelectric, and dielectric properties of lanthanum-gallium tantalate crystals at temperatures of 20–600°C

Measurements of the temperature variations in the relative dielectric constants $$ \varepsilon_{33}^T/{\varepsilon_0} $$ , $$ \varepsilon_{11}^T/{\varepsilon_0} $$ ,and $$ \varepsilon_{22}^T/\varepsilon {}_0 $$ , conductivities g11, g22, and g33, elastic constants $$ C_{11}^D $$ , $$ C_{66}^D $$ , and $$ S_{22}^E $$ , and electromechanical coupling constants kt, k26, and k12 of lanthanum-gallium tantalate over temperatures of 20–600°C are reported. Data are presented on the effect of lifetime (breakdown) testing on these characteristics of the piezoelectric crystals after retention at a temperature of 625°C for 250 h.