Improved structural and magnetic properties of cobalt nanoferrites: Influence of sintering temperature

The influence of heat treatment on the structural, morphological and magnetic properties of CoFe2O4 nanopowder synthesised by a citrate precursor method is investigated. The studies were done using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Fourier transform Infrared spectroscopy (FTIR) and Vibrating Sample Magnetometer (VSM). The results suggested that the specimen prepared by this method is purely crystalline having no other impurities and possessing improved magnetic properties. XRD analysis confirms the cubic spinel phase of CoFe2O4 nanoparticles with crystallite size is in the range 38–49 nm. SEM image confirms the formation of cubic grains with an average grain size of 80 nm. FTIR studies show the occurrence of the absorption bands between 470−420 cm−1 and 590−530 cm−1 corresponding to the strong metal oxide bonds in tetrahedral (A-site) and octahedral (B-site), respectively. M–H measurements verifies the strong influence of synthesis conditions and crystal size on the magnetic properties of ferrite nanocrystals. Specific saturation magnetization (Ms) value increases from 54 emu/g to 74 emu/g as sintering temperature increases from 900 to 1100 °C.