Enhancement in dielectric and ferroelectric properties of lead free Bi0.5(Na0.5K0.5)0.5TiO3 ceramics by Sb-doping

Abstract: Lead free piezoelectric Bi0.5(Na0.5K0.5)0.5TiO3 (pure and 1wt.%, 2wt.%, 4wt.% Sb-doped) ceramics were synthesized away from its MPB. The crystalline nature of the BNKT ceramic was studied by XRD and SEM. Depolarization temperature (T d ) and transition temperature (T c ) were observed through phase transitions in dielectric studies which were found to increase after Sb-doping, thus increasing its usable temperature range. In the study of relaxation behavior, the activation energy for relaxation was found to be 0.33, 0.43, 0.57 and 0.56eV for pure and Sb-doped samples, respectively. All samples were found to exhibit normal Curie–Weiss law above their T c . Doping of Sb was found to restrain the diffused character of the pure sample. In P–E loop, Sb-doping was found to increase the ferroelectric properties. Pure and Sb-doped BNKT ceramics exhibited high values of piezoelectric charge coefficient (d 33) as 115, 121, 129 and 100pC/N, respectively. [Copyright &y& Elsevier]