Effect of Cobalt Dopant on the Structural, Magnetic and Dielectric Properties of Fe3O4 Nanoparticles Prepared by Co-precipitation Method

Co-doped magnetite powders were successfully synthesized by the co-precipitation method. Structural, morphological, magnetic and electrical properties were investigated using x-ray diffraction (XRD), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), a vibrating sample magnetometer (VSM), ac conductivity and dielectric measurements. X-ray diffraction demonstrated that all the synthesized samples are cubic spinel structure with a space group of Fd3 m. Structural parameters such as crystallite size and lattice constant were calculated. FTIR analysis showed the two characteristic ferrite bands around 590 cm(-1) and 405 cm(-1) which are attributed to the stretching frequency of the tetrahedral and octahedral sites. TEM showed nearly homogeneous spherical shape particles with some irregularity in shape. VSM measurements of the powder exhibited ferromagnetic characteristics. The doping with Co2+ increases the coercivity (Hc) and remanance magnetization (Mr). The ac conductivity, dielectric constant and loss tangent measurements as a function of frequency and temperature show composition dependence.