Polarization behavior of‘ lead-free 0.94(Bi_0.5Na_0.5)TiO₃-0.06BaTiO₃ thin films with enhanced ferroelectric properties

(Bi_0.5Na_0.5)TiO₃ based ferroelectric lead-free thin films have great potential for modern micro-devices. However, the multicomponent feature and volatile nature of Bi/Na makes the achievement of high quality films challenging. In this work, the morphotropic phase boundary composition, 0.94(Bi_0.5Na_0.5)TiO₃-0.06BaTiO₃ thin films were successfully prepared by CSD method. Dense films with low dielectric loss and low leakage current density were obtained. A well-defined polarization hysteresis loop with a high remnant polarization was observed in the thin films. Moreover, the polarization behavior of the film at original state, under electric field and upon heating was investigated by PFM. A self-polarization and asymmetric domain switching behavior were observed. High temperature induced depolarization and the self-polarization recovered upon cooling. The thin films with good quality show a promising potential for the application in electrical devices, and the in-depth investigation of the polarization behavior improves the understanding of ferroelectric and piezoelectric properties of thin films.