Origin of enhanced piezoelectric properties revealed through electric field driven studies in 0.94(Na_0.5Bi_0.5TiO₃)−0.06(Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃) ceramics

A single phase 0.94(Na_0.5Bi_0.5TiO₃)–0.06(Ba_0.85Ca_0.15Ti_0.9Zr_0.1O₃) solid solution (i.e., BCZT-0.06) is prepared using a conventional solid-state sintering route with enhanced piezo and ferroelectric properties as compared to Na_0.5Bi_0.5TiO₃ (NBT). In the context of understanding the origin of enhanced piezoelectric properties in a BCZT-0.06 specimen, electric field driven studies on different length scales, viz., global, local, and electronic structure, are carried out using x-ray/neutron diffraction, Raman scattering, and UV–Vis spectroscopic techniques. An analysis on different length scales of the electric field-driven BCZT-0.06 specimen displays minimum rhombohedral lattice distortion (δ_r), reduced homogeneous lattice strain (δ), octahedral strain (ζ), and pronounced Ti-cation displacement along the polar [111] direction as compared to parent NBT. The enhanced ferro and piezoelectric responses observed in the BCZT-0.06 specimen have been attributed to the ease of non-180° domain re-orientation, domain switching, and domain wall motion due to reduced strain coupled with a polarization extension mechanism.