Structural, Morphological, and Magnetic Study of CoFe_2-xDy_xO₄ (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1) Nanoparticles Prepared by Co-precipitation

The change in the behavior of pristine cobalt ferrite on doping it with rare-earth (RE) metal ions has been investigated. The CoFe_2-xDy_xO₄ (where x = 0–0.1, with stepsize of 0.02) nanomaterials were synthesized by the co-precipitation method and corresponding morphological, structural, optical, and magnetic properties were observed. The x-ray diffraction (XRD) spectra revealed that all the prepared samples show a crystalline nature and that the crystallite size reduces with increasing dysprosium (Dy) concentration from 21 to 9 nm for x = 0.02 to x = 0.1. The Fourier-transform infrared spectroscopy (FTIR) spectra in the 4000–400 cm⁻¹ range supported the material formation. Diffused reflectance spectroscopy (DRS) was used for the energy bandgap calculation. Field-emission scanning electron microscopy (FESEM)–energy dispersive x-ray spectroscopy (EDAX) spectra showed the surface morphology and elemental composition of the materials and no peaks corresponding to other elements were observed. Room-temperature Vibrating sample magnetometer (VSM) studies at a field of 7 T revealed that the sample with x = 0.02 had the highest value of saturation magnetization at 77.39 emu/g, which is even greater than the CoFe₂O₄ sample, while the sample composition x = 0.1 had the least saturation magnetization of 36.41 emu/g. This reduction was brought on by the lower magnetic interactions between the RE³⁺ and Fe³⁺ ions. Such materials can have applications in optoelectronic, magnetic hyperthermia, and high-frequency devices.