Dielectric and piezoelectric properties of microwave processed Sm substituted PCT ceramics

The effect of samarium substitution on the structural, dielectric and piezoelectric properties of lead calcium titanate ceramics was investigated. Dense ceramics with nominal composition Pb0.76-3x/2SmxCa0.24Ti0.98Mn0.02O3 (x = 0-0.08) were fabricated by a novel, simple, energy and time efficient, and environment friendly microwave sintering process. The samples were sintered at 11000C for 30 min. All the compositions show single phase with tetragonal structure. Tetragonality decreases and relative density increases with increase in samarium substitution. The variation of the dielectric constant with temperature shows a ferroelectric phase transition and the transition temperature decreases with increase in the amount of samarium. Diffusivity increases with samarium substitution. All the compositions show well-defined ferroelectric behaviour. The electromechanical thickness coupling coefficient (kt) and piezoelectric longitudinal coefficient (d33) showed an increasing trend whereas the electromechanical planar coupling coefficient (kp) and the magnitude of the piezoelectric transverse longitudinal coefficient (d31) showed a decreasing trend with increase in samarium substitution level, which in turn results in an increase in electromechanical anisotropy