Enhanced ferroelectricity in Ti-doped multiferroic BiFeO3 thin films

Ti 4 + ion-doped BiFeO3 thin films were prepared by sol-gel spin-coating technique on (111)Pt∕Ti∕SiO2∕Si substrates. X-ray diffraction and scanning electron microscope revealed the single phase, and good surface and cross-section morphologies of the films, respectively. Leakage current density measurement indicated that the quality of the BiFeO3 films was improved by Ti4+ doping. By introducing a small amount of Ti ions into the sol-gel solution-processed BiFeO3 films, large enhancement in both remnant and saturation polarizations of the doped-BiFeO3 films in comparisons with the undoped BiFeO3 films was observed, due to the reduced leakage current, stabilization of the ferroelectric distortion by Ti4+, and more homogenous microstructure.