Electromechanical and piezoelectric studies of lanthanum modified lead titanate ceramics

Electromechanical and piezoelectric properties of lanthanum modified ceramics prepared by conventional solid state reaction method with lanthanum variation from 2 to 20 mol% are reported. The samples poled in silicone oil at 150 deg. C under the application of 30 kV cm-1 electric field exhibit increase in electromechanical thickness coupling coefficient (kt) and piezoelectric longitudinal coefficient (d33) with increase in lanthanum substitution. Their maximum values are attained at 15 mol% lanthanum composition. Electromechanical planar coupling coefficient (kp) and piezoelectric traverse longitudinal coefficient (d31), however, do not exhibit much dependence on lanthanum substitution