Multiferroic Properties of Co Doped BiFeO3 and Some Composite Films

Bi(Fe1-xCox)O-3 (BFCO) material and the composite based on doped Bi4Ti3O12/CoFe2O4 was synthesized by solution route for various compositions and films were deposited by spin coating on Pt substrate (Pt/Ti/SiO2/Si). Structural, ferroelectric, and ferromagnetic properties were investigated, respectively, using x-ray diffraction, Raman spectroscopy, VSM, and ferroelectric probe. X-ray diffraction patterns shows intense (110) peak of BFO in Bi(Fe1-xCox)O-3 with space group R3c and distorted rhombohedral perovskite structure without impure phase. The ferromagnetic response (M - H) showed room temperature magnetization of similar to 3 emu/cm(3) and coercive field Hc similar to 200 Oe for Bi(Fe0.98Co0.02)O-3 films. The ferroelectrics response shows week remnant polarizations (P-r) = 0.4 mu C cm(-2) for Bi(Fe0.98Co0.02)O-3 at room temperature, but saturation was not observed. The composite film of multilayer structures Bi3.5Nd0.5Ti3O12/CoFe2O4 shows composite phase, with considerable ferroelectric and ferromagnetic responses at room temperature.