Synthesis, crystal structure and magnetic properties of iron oxides nanoparticles for biomedical applications

摘要

Magnetic Fe_3O_4 nanoparticles have been synthesised by two methods: co-precipitation using a range of Fe~(3+) and Fe~(2+) raw materials; oxidative hydrolysis using various Fe~(2+) salts. X-ray diffraction analysis shows that most of the samples prepared by the co-precipitation method resulted in a mixture of two iron oxide phases (Fe_2_3 and Fe_3O_4) with the presence of impurities (unreacted precursors) while using the oxidative hydrolysis method, Fe_3O_4 was found to be a major product. Magnetic measurements confirm the results obtained by X-ray diffraction. The sample prepared using FeSO_4 as precursor in urea and PEG 200 at 40-50℃ for 3 hours (nominated as E2-) gives an average crystallites size around 70 nm, a saturation magnetisation Ms = 75 emu/g, a remanence of Mr = 12 emu/g and a coercivity of Hc = 110 kOe, which can be a good candidate for biomedical applications.