IMF2017

Perovskite-based ferroelectric materials are an important class of functional materials and a key topic in materials science. One of the challenges remain however to build rigorous structure-property relationships based on the atomic-level information. In this context, we have applied total elastic scattering technique which manifests pair distribution functions, and inelastic Raman scattering to a series of popular ferroelectric solid solutions such as BiScO₃-PbTiO₃, BiMg_1/2Ti_1/2O₃-PbTiO₃, and NaBiTiO₃-BaTiO₃, in order to understand the much-debated topic of composition-driven structural phase transitions leading to enhancement of the physical properties at a critical composition, termed as ‘Morphotropic Phase Boundary’ (MPB). In particular, we have refined structural models implementing reverse Monte Carlo technique against the experimental PDFs to depict the composition-induced structural changes in term of magnitudes and directions of the local polarization vector derived from the analysis of the local environment of the individual cation. Combined with concomitant development of the phonon modes, the results not only provided atomistic features to relate the observed properties, but also a new approach to conceive the structure-property connections for complex ferroelectric systems.