An investigation on synthesis and magnetic properties of nanoparticles of Cobalt Ferrite coated with SiO2

SiO2-coated Cobalt Ferrite (CoFe2O4) nanoparticles were obtained by the hydrolysis of tetraethylorthosilicate in the presence of CoFe2O4 nanoparticles in co-precipitation. The effects of SiO2-coating on the magnetic properties of CoFe2O4 nanoparticles were investigated. The structural, morphological and magnetic properties of as-prepared sample were characterization by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, transmission electron microscopy (TEM), Field emission scanning electron microscopy/energy dispersive x-ray analysis (FESEM-EDAX) and magnetic measurements were investigated using vibrating sample magnetometer (VSM). The morphology analysis confirmed that the obtained composite nanoparticles consisted of CoFe2O4 coated by SiO2. It was shown that the saturation magnetization and coercivity of CoFe2O4 decreased after SiO2 coating, which can be interpreted by the interparticle dipole-dipole interactions related to the magnetic particle volume fraction in the composite nanoparticles.