Synthesis and characterization of CoFe2O4 hollow spheres

CoFe2O4 hollow spheres with sizes ranging from 600 nm to I pm were prepared through hydrothermal treatment of an aqueous solution containing glucose, ammonium iron(II) sulfate hexahydrate [(NH4)(2)Fe(SO4)(2)center dot 6H(2)O], and cobalt(Il) sulfate heptahydrate [COSO4 center dot 7H(2)O], followed by calcination. The wall of the CoFe2O4 hollow spheres is composed of CoFe2O4 spinel nanoparticles with a size of ca. 30 nm and wall thickness of ca. 150 nm. Magnetic characterization indicates high coercivity and low saturation magnetization, which indicate potential applications as high-density magnetic recording materials and drug carriers. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008).