Local structure underlying anomalous tetragonal distortions in BiFeO3-PbTiO3 ferroelectrics

This is the authors' abstract. We don't add key points for this paper.

The local structure of tetragonal BiFeO3-PbTiO3 solid solutions featuring anomalous lattice distortions has been determined using simultaneous fitting of neutron total scattering and extended X-ray absorption fine structure data. On the local scale, the large tetragonal distortion, promoted by the displacements of the A-cations (Bi and Pb), is accommodated primarily by the [FeO6] octahedra, even though both Fe and Ti acquire (5+1)-fold coordination. Bi cations exhibit considerably larger displacements than Pb. The combination of the A-cation displacements and the ability of M-cations to adopt 5-fold coordination is suggested as key for stabilizing the large tetragonality in BiMO3-PbTiO3 systems.