Na 1/2 Bi 1/2 TiO 3 -based (NBT-based) ceramics offer a viable option to replace lead-based materials for highpower applications as they are characterized by a stable mechanical quality factor with increasing vibration velocity in comparison to lead-based piezoceramics. Recently, the minor and stable extrinsic contributions were revealed as the origin for the stability of the mechanical quality factor with increasing vibration velocity. This work identifies the very unusual high poling degree as cause for the small extrinsic contributions. To this end, complete pole figure densities have been quantified and correlated to the piezoelectric coefficient and electromechanical quality factor. This hypothesis is further strengthened by correlating the piezoelectric constant (sum of intrinsic and extrinsic contributions) with the remanent polarization (correlates to remanent texturing degree). In order to assess a full picture of NBT-based piezoceramics, 0.94Na 1/2 Bi 1/2 TiO 3 -0.06BaTiO 3 has been considered with and without Zn doping and with quenching. It is compared to 0.79Na 1/2 Bi 1/2 TiO 3 -0.21 K 1/2 Bi 1/2 TiO 3 with and without Mg doping. Finally, a contrast to soft Pb(Zr 1/2 Ti 1/2 )O 3 (PZT) flushes out the impact of domain wall motion on the piezoelectric coefficient and the electromechanical quality factor. Whereas a PZT-based reference material exhibits a linear increase in the piezoelectric constant with increasing remanent polarization, the NBT-based materials deviate from the linear trend, indicating a decrease in extrinsic contributions.

A series of morphotropic phase boundary (MPB) compositions of (1-x) Na 1/2 Bi 1/2 TiO 3 -xBaTiO 3 (x = 0.05, 0.055, 0.06, 0.065, 0.07), with and without 0.5 mol% Zn-doping was synthesized using the solid-state route. The samples were characterized using X-ray diffraction, dielectric analysis, and electromechanical measurements (piezoelectric d 33 coefficient, coupling factor k p , mechanical quality factor Q m , and internal bias field E bias ). The increase in the ferroelectric-relaxor transition temperature upon Zn-doping was accompanied by a shift of the MPB toward the Na 1/2 Bi 1/2 TiO 3 -rich side of the phase diagram.Higher tetragonal phase fraction and increased tetragonal distortion were noted for Zn-doped (1 -x)Na 1/2 Bi 1/2 TiO 3 -xBaTiO 3 . In addition, ferroelectric hardening and the presence of an internal bias field (E bias ) were observed for all doped compositions. The piezoelectric constant d 33 and the coupling coefficient k p decreased by up to ∼30%, while a 4-to 6-fold increase in Q m was observed for the doped compositions. Apart from establishing a structure-property correlation, these results highlight the chemically induced shift of the phase diagram upon doping, which is a crucial factor in material selection for optimal performance and commercialization.