Magnetic behavior of Fe3O4@C nanofibers by a facile co-axial electrospinning method

Co-axially electrospun, magnetic Fe3O4@carbon (Fe3O4@C) nanofibers comprising Fe3O4particles in the core and carbon in the shell have been fabricated and their performances as magnetic material have been studied. The electrospun Fe3O4@C nanofibers have been characterized with x-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscope, x-ray photoelectron spectroscope (XPS), and superconducting quantum interference device magnetometer. The structural and microstructural analysis has given a brief idea about the pure Fe3O4and C phase formation and also the existence of smooth and continuous morphology of Fe3O4@C nanofibers. It has been shown that there exist two different oxidation states of Fe in the XPS spectrum. The magnetization hysteresis loop has been observed at low temperatures (5 K, 100 K) as well as at room temperature (300 K) which gives different magnetic parameters. Temperature dependent magnetic measurements (from 5 to 300 K) suggest the existence of Verwey transition for lower percentage of iron oxide content.