Influence of lead titanate additive on the structural and electrical properties of Na0.5Bi0.5TiO3-SrTiO3 piezoelectric ceramics

Abstract

Investigations of the structural and electrical properties of 0.40Na0.5Bi0.5TiO3-(0.6-x) SrTiO3- xPbTiO3 quaternary solid solutions (x = 0.08, 0.18, and 0.28) are presented in this paper. The solid solutions are synthesized using solid-state reaction techniques. X-ray diffraction (XRD) studies reveal that the solid solution is homogeneous and has a tetragonal structure with space group (P4mm) as well as the co-existence of tetragonal and cubic phases with 0.08 mol% lead titanate. The surface morphology of the material is observed using SEM, and reductions in grain sizes are observed with increasing PT. The dielectric properties of this solid solution, measured between room temperature and 673 K in the frequency range 1–100 kHz, showed good relaxor behaviour. The maximum dielectric constant (εr) ~ 3144 is observed at 413 K. Excellent P-E hysteresis loops for this solid solution confirm good ferroelectric properties, exhibiting a maximum at 55 kV/cm. Remanant polarization (Pr) and coercive field (EC) exhibit an increasing, decreasing and then a subsequent increasing trend with the increase in PT concentration. The piezoelectric coefficient (d33) measured on the poled samples exhibited a maximum of ~ 89 pC/N. The estimated energy storage density, (W) ~ 0.30 J/cm3, showed a superior energy storage performance. The excellent dielectric, piezoelectric and ferroelectric properties of the sodium bismuth titanate - strontium titanate-lead titanate system implied that the structure of the solid solutions approached the morphotropic phase boundary region, which enhances its potential for use in sensor and actuator applications.