Effects of Ti-doping on the structural, electrical and multiferroic properties of Bi2Fe4O9 thin films

Structural, electrical and multiferroic properties were investigated for the Bi2Fe4O9 and the Bi2Fe3.4Ti0.6O9+δ thin films prepared on Pt(111)/Ti/SiO2/Si(100) substrates by using a chemical solution deposition method. Both X-ray diffraction and Raman spectroscopy studies revealed that the Bi2Fe4O9 and the Bi2Fe3.4Ti0.6O9+δ thin films were crystallized in a single phase of polycrystalline orthorhombic structure. From leakage current densities and ferroelectric hysteresis loops, a low order of leakage current density of 9.23×10−7 A/cm2 and an enhanced remnant polarization (2Pr) of 1.5 μC/cm2 with a low coercive field of 126 kV/cm were observed for the Bi2Fe3.4Ti0.6O9+δ thin film. The Bi2Fe4O9 and the Bi2Fe3.4Ti0.6O9+δ thin films showed a weak ferromagnetism at room temperature. On comparing with a bulk ceramic form of Bi2Fe4O9, in thin film form it showed remarkably enhanced multiferroic properties.