Fe_3O_4 nanoparticles were synthesized by a solvothermal method with reaction system of H_2O and ethanol in a high-pressure autoclave.The products were confirmed by XRD and FTIR.The obtained Fe_3O_4 nanoparticles have the long rod-like morphology with 200~500nm in length and 20~30nm in diameter under the observation of high-resolution transmission electron microscopy.The saturation magnetization of Fe_3O_4 nanoparticles is 64.75emu/g,which shows the good magnetic properties.The formation mechanism of format...