A comparison between tetragonal-rhombohedral and tetragonal-orthorhombic phase boundaries on piezoelectricity enhancement

We made a detailed comparison of physical properties between the tetragonal-rhombohedral (T-R) phase boundary (in the Ba(SnTi)O _3-x(BaCa)TiO ₃ system) and the tetragonal-orthorhombic (T-O) phase boundary (in the Ba(Sn _xTi _1x)O ₃ system). The contrasting results suggest that the T-R phase boundary enhances the piezoelectricity more significantly than the T-O phase boundary. Such difference is considered to stem from the dissimilar anisotropy for polarization rotation, the different elastic softening and the different domain wall contribution between T-R and T-O phase boundaries.