Polyethylene glycol-assisted hydrothermal growth of magnetite nanowires: Synthesis and magnetic properties

Magnetite (Fe3O4) nanowires with diameters around 25 nm and lengths up to 1.5 μm have been successfully synthesized using a simple polyethylene glycol (PEG)-assisted hydrothermal technique. Powder X-ray diffraction pattern, energy-dispersive X-ray spectroscopy, and selected-area electron diffraction measurements indicated that the as-synthesized product is pure single-phase Fe3O4 with a good crystalline state. The size, morphology, and structural features of the as-prepared Fe3O4 were investigated by transmission electron microscopy and scanning electron microscopy. Effects of reaction-controlling parameters such as the volume ratio of PEG to water, operating temperature, and duration of process have been investigated in detail. Vibrating sample magnetometer measurements show that Fe3O4 nanowires exhibit a ferrimagnetic behavior at room temperature; a saturation magnetization of 90.94 emu/g is obtained, which is essentially higher than the reported values. A reaction mechanism for the nanowire formation is also proposed.