Magnetic properties of zinc-substituted cobalt ferric oxide nanoparticles: Correlation with annealing temperature and particle size

Nanocrystalline zinc (Zn)-substituted cobalt ferric oxide (CoFe2O4) was prepared through chemical co-precipitation; the prepared samples were annealed at 600 °C, 750 °C and 900 °C. The crystallite size, microstructure and magnetic properties of the prepared and annealed samples were studied by using X-ray powder diffraction (XRD), Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Energy Dispersive Spectroscopy (EDS) and Vibrating Sample Magnetometry. The structural investigations carried out by XRD reveal that the particle size and lattice constant of single phase spinal structured Zn substituted CoFe2O4 increase with the increase of annealing temperature. The FTIR spectra for the samples measured in the range of 4000–400 cm−1 exhibit symmetric stretching mode of vibration of tetrahedral and octahedral sites. Furthermore, Zn substituted CoFe2O4 nanoparticles have the crystallite size in the range ~13–65 nm, as confirmed by TEM. The elemental analysis was obtained from EDS. Finally, increased annealing temperature resulting in increased particle size and the impact on magnetic properties of CoFe2O4 nanoparticles is a significant finding of this study.