A Comparative Study for the Effect of Calcination on the Temperature-Dependant Magnetic Properties of Cobalt Ferrite Nanoparticles.

A wet chemical method was used to synthesize the cobalt ferrite nanoparticles (CFN) and further calcined at 1000°C. The effect of calcination onto the structure, morphology and crystallinity of the synthesized material was examined by different characterization techniques such as field-emission scanning electron microscopy (FE-SEM), Fourier transform infra-red (FTIR), thermo-gravimetric analysis (TGA) and X-ray diffraction (XRD). The results identified that after calcination at 1000°C, the cobalt ferrite nanoparticles become more stable, bigger in crystallite size, lattice constant and greater cation distribution between octahedral and tetrahedral sites as compared to uncalcined parent CFN. Furthermore, the magnetic properties of both parent and calcined cobalt ferrite nanoparticles were also determined by the vibrating-sample magnetometer. The results declared that the saturation magnetization increased with the increased calcination while the converse is true for coercivity. The reason behind the decrease of coercivity is the pining effect at gain boundary. The hysteresis loop slowly levels as the temperature moves toward Curie temperature. [ABSTRACT FROM AUTHOR]