S. Rostamzadehmansoor - Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran.
M. S. Sadjadi - Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran.
K. Zare - Department of Chemistry, Science and Research Branch, Islamic Azad University, Tehran, Iran.

SiO۲-coated Cobalt Ferrite (CoFe۲O۴) nanoparticles were obtained by the hydrolysis of tetraethylorthosilicate in the presence of CoFe۲O۴ nanoparticles in co-precipitation. The effects of SiO۲coating on the magnetic properties of CoFe۲O۴ 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 CoFe۲O۴ coated by SiO۲. It was shown that the saturation magnetization and coercivity of CoFe۲O۴ decreased after SiO۲ coating, which can be interpreted by the interparticle dipole-dipole interactions related to the magnetic particle volume fraction in the composite nanoparticles.

Synthesis, Magnetic Properties, SiO۲-coated cobalt ferrite, nanoparticles, X-ray diffraction (XRD), Energy dispersive