Multiferroic Properties of Co Doped BiFeO₃ and Some Composite Films

Abstract

Bi(Fe_1-xCo_x)O₃ (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(Fe_1-xCo_x)O₃ with space group R3c and distorted rhombohedral perovskite structure without impure phase. The ferromagnetic response (M - H) showed room temperature magnetization of ∼3 emu/cm³ and coercive field Hc ∼200 Oe for Bi(Fe_0.98Co_0.02)O₃ films. The ferroelectrics response shows week remnant polarizations (P_r) = 0.4 μC cm⁻² for Bi(Fe_0.98Co_0.02)O₃ at room temperature, but saturation was not observed. The composite film of multilayer structures Bi_3.5Nd_0.5Ti₃O₁₂/CoFe₂O₄ shows composite phase, with considerable ferroelectric and ferromagnetic responses at room temperature.

Acknowledgment

This work was supported by DoE-EPSCoR Grant No. DE-SG02–08ER46526 and is gratefully appreciated.