Synthesis and ferroelectric behavior of Gd doped BNT ceramics

In the present work, polycrystalline (Bi1−xGdx)0.5Na0.5TiO3 (BGNT) ceramics with low amount of rare earth ion Gd3+ (x = 0, 0.02, 0.03, 0.04) have been synthesized by a semi-wet technique. XRD patterns show single phase formation for all the samples with a rhombohedral structure at room temperature. FE-SEM images show decrease in grain size with Gd concentration. The temperature dependence of dielectric constant has revealed that the depolarization temperature 'Td' decreases with increasing x and the temperature 'Tm' of maximum dielectric constant increases initially for x = 0.02 thereafter decreases. All the samples have shown saturated hysteresis (P-E) loop at room temperature. The BGNT ceramic system for composition, x = 0.02 exhibits improved piezoelectric properties and strong ferroelectricity. With increasing temperature, polarization has been found to be reduced and deformed P-E loops are observed around 'Td'.