Comparative study on doping effects in Bi_1−xDy_xFe_1−yMn_yO₃ nanoparticles fabricated by sol-gel technique

We have studied the optical, electrical and magnetic properties of Dy and Mn doped BiFeO₃ nanoparticle synthesized by the sol-gel technique. In the doped samples, a transition of crystal structure was demonstrated by XRD. With increasing x from 0.00 to 0.10 and y from 0.00 to 0.05, the optical band gap of Bi_1−xDy_xFe_1−yMn_yO₃ nanoparticles decreases and can be interpreted by the decreased particle size and the increased internal stress of samples, which caused by Dy, Mn doping. According to the data from X-ray photoelectron spectroscopy, the doping of Dy³⁺ and Mn²⁺ can availably restrain the transform from Fe³⁺ to Fe²⁺. A small leakage current density and large value of saturation magnetization are observed for the co-doped samples. Therefore, the doping of (Dy, Mn) is an effective mean to strengthen the multiferroic behavior of the nanoparticles.