Lattice distortion and orbital hybridization in NdFeO3–PbTiO3 ferroelectric thin films

Abstract

Single-phase xNdFeO₃–(1 − x)PbTiO₃ thin films with different dopant contents were fabricated on the Pt(111)/Ti/SiO₂/Si substrate by a sol–gel route. Grain size was influenced by the dopant content effectively. A synchrotron radiation X-ray diffraction study revealed a reduced tetragonality (c/a) of the PbTiO₃ lattice in the films. Distortion of the TiO₆ octahedron was weakened, as investigated by Raman scattering and X-ray absorption spectra. An electronic structural study indicated that the hybridizations between O 2p and Pb 6s and Ti 3d orbitals were weakened. The decrease of lattice distortion and orbital hybridization gives rise to degradation of the ferroelectric nature in the films.