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

Co-axially electrospun, magnetic FeO@carbon (FeO@C) nanofibers comprising FeOparticles in the core and carbon in the shell have been fabricated and their performances as magnetic material have been studied. The electrospun FeO@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 FeOand C phase formation and also the existence of smooth and continuous morphology of FeO@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.