Facile synthesis of superparamagnetic Fe₃O₄ nanoparticles just using ferric citrate and water

Fe₃O₄ nanoparticles were synthesized by a facile one-pot hydrothermal process just using ferric citrate and water without any additional reagent and post-treatment. The temperature of hydrothermal reaction had important influence on the crystallinity and magnetic property of Fe₃O₄ samples. Fe₃O₄ sample synthesized at 200 °C for 24 h showed a narrow size distribution (4 to 8 nm in diameter), and exhibited apparent superparamagnetism with saturated magnetization of 55.1 emu/g. The narrow size distribution and superparamagnetism were the interesting features of these Fe₃O₄ nanoparticles.