Effect of Cobalt Substitution on the Structural and Magnetic Properties of Bismuth Ferrite Powders

Abstract

BiFeO3 (BFO) is a multiferroic material with excellent ferroelectric properties but with poor magnetic behavior. Therefore, we focused principally on the enhancement of the magnetic order of BFO. These multiferroic properties make BFO an excellent candidate for magnetoelectric devices at room temperature. Pure and Co-BiFeO3 powders were successfully synthesized via the sol–gel method at 700 °C. The effect of Co substitution on the corresponding structural and magnetic properties of BFO was studied. X-ray diffraction and Fourier Transform Infrared Spectroscopy measurements confirmed the rhombohedral perovskite structure in all samples. A secondary phase of CoFe2O4 (CFO) was detected for 9, 10, and 15% of Co doping. The scanning electron microscopy images of the Co-BFO particles showed a reduction in the particle size compared to the pure BFO powders. Vibrating sample magnetometry measurements evidenced the ferromagnetic hysteresis loop for the Co-BFO powders with values of saturation magnetization of 4.1 emu/g and a coercivity of 1083 Oe for 15% of Co doping. In this work, we report impurity free samples with notable magnetic properties at the same time, which is a difficult challenge in bismuth ferrite synthesis. This is the first step for later applications in future technology.