We report on the ferroelectric properties of multiphase BiFeO3 thin films grown under varying oxygen deposition pressures. The dominant phases formed in the film change continuously from a mixture of BiFeO3 and Bi2O3 to a mixture of BiFeO3 and Fe2O3 as the pressure is varied. Xray diffraction and transmission electron microscopy revealed that ail epitaxial nanocorriposite of BiFeO3 and Fe203 grew at deposition pressures of approximately 20 m Torr. The BiFeO3 grains in the BiFeO3-Fe2O3 nanocomposites were completely relaxed and unstrained. At room temperature the BiFeO3-Fe2O3 nanocomposite film was characterized by a high switchable polarization (60 mu C/cm(2)) and a low leakage current density (approximate to 1 X 10(-4) A/cm(2) at 250 V/cm). (C) 2007 Elsevier B.V. All rights reserved.