We report the vapor phase growth of partially filled graphitic fibers, 20-30 nm in diameter and up to a micron in length, during a manganese catalyzed carbon electric arc discharge. The fiber morphology resembles that of catalytic chemical vapor deposited carbon filaments but the inside hollow contains intermittent precipitates and continuous filling of Mn that at times occupy >50% of fiber lengths. Transmission electron microscopy and electron energy loss line spectra show that the fillings form as solid cores and may correspond to pure metal.

• Received 25 October 1993

DOI:https://doi.org/10.1103/PhysRevLett.72.1722