Synthesis of magnetic composite of iron compounds/carbon nanotubes in chemical vapor deposition

The chemical vapor deposition (CVD) synthesis of magnetic composite of iron compounds/carbon nanotubes (com-CNT) has been successfully carried out in various pressures using a catalyst of iron oxide/carbon. The temperatures were set at 800 °C for 10 minutes reaction time. Nitrogen (N₂) gas in 20 Torr was flown in followed by ethanol vapor until the final pressure reached 80 and 100 Torr without added air, and 180 Torr with added air. The formation of com-CNT was confirmed by shifted X-ray diffraction (XRD) peak of graphite from 26.53 ° to 25.53 ° which were highly considered to the other carbon allotropes with sp² hybridized carbon atom hybridization structures. The higher pressure with added atmospheric air led to the excessive oxidation which influenced the growth of com-CNT. Transmission electron microscopy (TEM) analysis observed CNT filled by catalyst particles which suggested as magnetic phase induced the magnetic property of com-CNT. The magnetic property of the composites was roughly estimated by observing the attraction of com-CNT toward a permanent magnet. The rough value of the lowest electrical resistance was owned by com-CNT produced in the lower pressure condition with no air added. (author)