Local Structure of Ferroelectric Materials

Most of the ferroelectric and piezoelectric materials used in transducers and electronics are complex mixed-ion alloys, in which atomic disorder plays an important role in the ferroelectric properties. The extreme case is relaxor ferroelectric solids with diffuse ferroelectric transition and glass-like relaxation behavior. In this review I discuss how advanced characterization techniques, such as neutron scattering, enabled a determination of the local structure and facilitated the understanding of the ferroelectric and piezoelectric properties of these complex systems. In particular, I focus on the role of Pb²⁺ ions in mixed ferroelectrics and the atomistic mechanism of relaxor ferroelectrics.