Role of doped nitrogen and sulphur in cobalt/cobalt-zirconium nanoferrites synthesized by facile methods

Abstract

Nitrogen/sulphur doped cobalt and cobalt zirconium mixed nanoparticles were synthesised by coprecipitation/wet impregnation methods. X-ray diffraction and X-ray fluorescence spectroscopic studies reveal the formation of monophasic cubic spinel structure with expected stoichiometries. Average crystallite sizes vary in the range of 17–26 nm. X-ray photoelectron and energy dispersive X-ray spectroscopic studies indicate the successful incorporation of non-metal elements into the ferrite lattice. Fourier-Transform infrared and Raman spectroscopic studies confirm the presence of stable cubic spinel ferrite structure of cobalt ferrite after doping. Evidences point towards the insertion of sulphur and nitrogen as cations, contrary to other metal oxides like titania. Thermal stability studies prove that ferrite formation is a continuous process producing stable crystalline spinel nanoparticles around 700 °C. Magnetic measurements at room temperature indicate decrease in saturation magnetisation with doping whereas coercivity increases with reduction in the particle size. DC resistivity measurements in the range of 30–400 °C show decrease in resistivity with increase in temperature, indicating semiconducting behaviour. The results of microstructural, magnetic and dielectric properties suggest that the prepared nanoparticles are suitable for catalysis, adsorption recycle, high frequency devices, inductors and biomedical applications.