LAUSR

Abstract Cobalt ferrite nanoparticles CoFe 2 O 4 were synthesized using the thermal decomposition method; subsequently the NPs were functionalized using poli vinyl pyrrolidone (PVP) cetyl trimethyl ammonium bromide (CTAB) and polyethylene glycol (PEG) as dispersing agent. Surface modification with silica SiO 2 was made using the Stober method and tetraethyl orthosilicate (TEOS) as precursor. The purpose of this study is to investigate the influence of the different dispersing agents on the structure and therefore on the magnetic properties of the CoFe 2 O 4 / SiO 2 nanocomposites. Structural characterization was carried out using: X-ray diffraction (XRD), infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Magnetic properties were evaluated using a vibrating sample magnetometer (VSM) at room temperature. Our results revealed that the structural and magnetic properties of the CoFe 2 O 4 / SiO 2 nanocomposites were significantly different depending of the type of dispersing agents used before the surface modification with silica SiO 2 .