LAUSR

Abstract Copper ferrite (CuFe2O4) nanoparticles were synthesized by sol–gel auto combustion method using cow-urine as a chelating agent. The obtained ferrite nanoparticles are heat treated at different temperatures (450 °C and 750 °C) in order to study their size dependent structural and magnetic properties. Energy Dispersive X-ray (EDX) spectra showed the maintenance of stoichiometry of elemental composition of ferrite system. Secondary phases of CuO and α-Fe2O3 are identified from the X-ray diffraction (XRD) patterns and these phases seem to be reducing with the heat treatment improving the ferrite phase of the sample. A systematic variation of structural parameters that is decrease of lattice parameter (8.379–8.369 A) and increase in average crystallite size (13.7–18.2 nm) have been found with the heat treatment. The average particle size estimated from Field Emission Scanning Electron Microscopy (FE-SEM) micrographs (14.5–22.3 nm) is slightly bigger than the average crystallite size estimated from XRD is due to the coalescence of crystallites which can be identified in FE-SEM micrographs. The obtained vibrational frequencies in the range of 550–450 cm−1 confirm the ferrite phase of copper ferrite. The splitting observed at the octahedral vibrational band is assigned to the secondary phase of α-Fe2O3. The saturation magnetization (Ms) is increasing with the heat treatment and highest value of Ms = 35.4 emu/g was reported. The results are discussed in terms of variation of particle sizes presuming the core–shell interactions.