Structural and electrical properties of the sol-gel derived multiferroic BiFeO3 monolayer and NiTiO3-BiFeO3 bilayer thin films

In this paper, the multiferroic BeFiO(3) monolayer and NiTiO3-BiFeO3 bilayer thin films were fabricated by spin-coating method on the SrRuO3/n(+)-Si substrate. The structural and ferroelectric properties of multiferroic BeFiO(3) monolayer and NiTiO3-BiFeO3 bilayer thin films were investigated. Both multiferroic films showed the typical XRD patterns of the perovskite structure without presence of the second phase. The electrical properties, such as leakage current and remnant polarization, of the NiTiO3-BiFeO3 bilayer film were superior to those of BeFiO(3) monolayer film, which those values were 1.94x10(-4) A/cm(2) at electric field of 0.75 MV/cm and 14.05 mu C/cm(2), respectively. This outcome is due to the NiTiO3-BiFeO3 bilayer film with a high Schottky barrier height as well as a top NiTiO3 layer on the BiFeO3 film inducing the strain-induced polarization rotation and forming the strong domain-wall pinning.