magnetic iron oxide nanoparticles, polyethylene glycol, surfactant, superparamagnetic, chemical co-precipitation

in this study, magnetic iron oxide nanoparticles (fe3o4) with the size range of 20-30 nm were prepared by the modified controlled chemical co-precipitation method from the solution of ferrous/ferric mixed salt-solution in alkaline medium. in this process polyethylene glycol was used as a surfactant to prevent the solution from agglomeration. the prepared magnetic nanoparticles were characterized by x-ray diffraction (xrd) analysis,  scanning electron microscopy (sem) and vibrating-sample magnetometer (vsm). xrd image indicates the sole existence of inverse cubic spinel phase of magnetic iron oxide nanoparticles (fe3o4). sem image show that the dimension of magnetic iron oxide nanoparticles (fe3o4) is about 24 nm. vsm patterns demonstrate superparamagnetic properties of magnetic nanoparticles.