Preparation and structural instability of the 0.1BiFeO3-0.9Bi4Ti3O12 system

The solid solution of 0.1BiFeO3-0.9Bi4Ti3O12 (BF-BT) with bismuth-layered perovskite structure was obtained by conventional solid-state reaction. The lattice instability of BF-BT has been investigated by variable-temperature Raman scattering and X-ray diffraction. The results showed that there was a ferroelectric phase transition in the 450∼550 °C region in terms of the evolution of temperature dependence of Raman scattering frequencies. Some changes at about 530 °C in the XRD lines, the lattice parameters (a, b and c) as well as the orthorhombic distortion b/a have been detected in the high temperature X-ray diffraction, which can be interpreted by a phase transition and it is in good agreement with the results of high temperature Raman scattering.