The relation between the local and the average structure of rhombohedral ferroelectric PbHf0.9Ti0.1O3 Original Research Article

The local structure of the rhombohedral perovskite PbHf0.9Ti0.1O3 was studied using Pb, Hf and Ti X-ray absorption fine structure (XAFS). XAFS data were analyzed by fitting a parameterized theoretical spectrum to the experimental data. It was found that the structure of the TiO6 octahedron is very different from the structure of the HfO6 octahedron. Furthermore, the Pb–O and Pb–Pb bonds have very large Debye–Waller factors indicating that Pb and O atoms are disordered about the rhombohedral positions down to 11 K. Despite the structural disorder, the local structure of PbHf0.9Ti0.1O3 resembles the rhombohedral average structure more than the structure of PbHfO3 or PbTiO3. Since PbHf1−xTixO3 and PbZr1−xTixO3 have very similar phase diagrams, it is reasonable to assume that the same structural features characterize rhombohedral PbZr1−xTixO3.