Synthesis of iron-filled carbon nanotubes with a great excess of ferrocene and their magnetic properties

Iron-filled carbon nanotubes (CNTs) were synthesized using a floating catalyst chemical vapor deposition method with a great excess of ferrocene (more than 30 mg/min of vaporization rate) at 800 ∘C. The amount of ferrocene is more than that in previous reports. The ferrocene was employed as both catalyst precursor and an iron source. Our observations indicate that the CNTs were more than 10 micrometer in length, with an outer diameter of 20–100 nm and inner diameter of 10–30 nm. The inner cavity of the CNTs was partial filled with iron nanowires. Magnetic property measurements reveal that the iron-filled CNTs exhibit an average coercivity of about 257.05 G.