Synthesis and magnetic properties of CoFe2O4 nanoparticles by using PEG as surfactant additive

CoFe2O4 nanoparticles with an average diameter of 25 nm and hexagonal and quadrangular shape were synthesized by a facile hydrothermal process at 180 degrees C. This method was versatile for synthesis of other spinel ferrites. By adjusting the reaction condition we can modify the size and morphology of the product. The synthesized product has good hard magnetic property. It was found that the addition of polyethylene glycol can elevate the crystallinity of CoFe2O4 and change the product morphology and cause the saturation magnetization of product increased. The function mechanism of the polyethylene glycol in the reaction system was also discussed in this paper. These magnetic material is promising material for high-density magnetic storage and medical diagnostics. (C) 2007 Elsevier B.V. All rights reserved.