Composition dependence of xBiFeO3-(1-x)PbTiO3 films prepared by sol-gel technique

Bismuth ferrite and lead titanate composite multiferroic films (xBiFeO3-(1-x)PbTiO3, BFO-PT films) were deposited on Pt/Ti/SiO2/Si substrates by sol-gel method. In this report, the value of x varies from 0.5 to 0.8. The composition dependence (dependence of x) of BFO-PT films is studied. X-ray diffraction analysis reveals that all films are well crystallized in tetragonal phase. It discovers that enhanced ferroelectricity and decreased coercive field can be obtained by reducing the content of BFO (decreasing x). Film for x=0.7 shows the optimized properties, with a very low leakage density about 3.3 × 10⁻⁷ A/cm² at 100kV/cm, maintaining the values of remanent polarization of 35.5 µC/cm² and coercive field of 165 kV/cm at 680 kv/cm at room temperature.