Magnetic properties of Fe3O4 nanoparticles having several different coatings

Fe3O4 is a magnetic material (ferrimagnet at room temperature), and its nanoparticles find wide applications in industry and biotechnology. In general, they are coated with suitable organic material to avoid their self-agglomeration. A variety of coating materials have been used and their choice largely depends on the applications of nanoparticles. This paper deals with the synthesis, characterization and study of magnetic properties of Fe3O4 particles having several different coatings, but similar magnetic properties. Nanoparticles were synthesized using a wet route involving co-precipitation of Fe(2+)and Fe3+ ions and they were coated with citric acid, ethylene diamine tetra acetic acid, tetramethyl ammonium hydroxide, polyethylene glycol and oleic acid using standard chemical methods. These particles were characterized using X-ray diffraction, transmission electron microscopy and Fourier transform infrared. Magnetization studies were carried out using a vibrating sample magnetometer and data have been analysed to obtain information about the magnetic moment on the particle and other parameters, such as saturation magnetization, structural defects and magnetocrystalline anisotropy.