Substantially enhanced ferroelectricity in Ti doped BiFeO₃films

Abstract

We have grown BiFeO3 (BFO) and 5% Ti doped BiFeO3 (BFTO) thin films on LaNiO3/Si structures by simple sol–gel deposition. X-ray diffraction analysis confirmed that BFO has an intense (1 1 0) peak and the BFTO film is randomly oriented and adopts a rhombohedrally distorted perovskite structure. No impure phase was identified in the two films. A cross section scanning image revealed that the BFMO film has homogeneous thickness. Surface scanning electron microscopy images indicated that the BFTO film has a more compact structure. The BFTO film showed larger remanent polarization (Pr) and a small coercive field. The Pr values are 16.0 µC cm−2 and 8.0 µC cm−2 and coercive fields are 189 kV cm−1 and 416 kV cm−1 for the BFTO and BFO films at the same applied electric field, respectively. Through the Ti substitution, the dielectric property is also enhanced and leakage conduction is reduced.