Dielectric and Ferroelectric Properties of Lead-Free [1-z{(Bi1-xLax)0.5(Na1-yLiy)0.5TiO3}-zBaTiO3] Ceramic System

Abstract

Lead-free specimens of [1-z{(Bi1-xLax)0.5(Na1-yLiy)0.5TiO3}-zBaTiO3] (BLNLT-BT, where x=0.04, y=0.025, and z=0, 0.02, 0.04, and 0.06) ceramic system were synthesized by a semiwet technique. In the present study, we have investigated the effect of Ba on the structure, morphology, and dielectric, ferroelectric, and piezoelectric properties of BLNLT system. The XRD patterns of all the specimens showed rhombohedral structure at room temperature. Field emission scanning electron microscopy images (FE-SEM) showed grain growth inhibition with Ba content in BLNLT system. The temperature dependence of dielectric constant revealed that the temperature of maximum dielectric constant “Tm” and depolarization temperature “Td” decreased for the sample z=0.06 and showed high value of dielectric constant with low dielectric loss. These samples exhibited nonlinear behaviour of hysteresis loop. The values of dielectric constant (εr), dissipation factor (tan δ), piezo charge coefficient (d33), remnant polarization (Pr), and coercive field (Ec) for the composition z=0.06 were 1495, 0.06, 20 pC/N, 5 μC/cm2, and 10.5 kV/cm, respectively.