Synergistic contributions of the poling field-induced changes in local structure on the piezoelectric properties of modified BaTiO₃system

Local structural heterogeneity is a key factor in improving the piezoelectric properties of non-centrosymmetric piezoelectric systems. This work investigates electric field-induced structural and microstructural changes at localized and average scales to elucidate the structure-property correlations that enhance piezoelectric performance in Sn-doped BaTiO 3 systems exhibiting coexisting phase boundaries. Despite showing field-induced structural phase transformation, the sample displays variations in piezocoefficient values with the nature of phase boundary compositions. Raman spectroscopy measurements reveal that the TiO 6 /SnO 6 octahedra near the tetragonal-orthorhombic phase boundary exhibit significantly greater poling field-induced structural heterogeneities in local structure compared to those near the orthorhombic-cubic phase boundary. X-ray absorption spectroscopic results on Ti and Sn K-edge in unpoled and poled samples reveal that the dipolar contribution responsible for the piezoelectricity originates from field-induced distortion associated with both TiO 6 and SnO 6 octahedra. Near the vicinity of the tetragonal-orthorhombic phase boundary, both the TiO 6 and SnO 6 contributions are cumulative and exhibit better piezoelectricity. On the other hand, at the orthorhombic-cubic phase boundary, the dipolar contributions from these octahedra are counterintuitive, resulting in a reduction of piezoelectricity. These results could provide a pathway to design materials with an enhanced piezoelectric response by considering various phase boundary aspects before applying a poling field prior to making them piezoactive.