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.