Synthesis, structure, and superconducting properties of NbC nanorods and nanoparticles

NbC nanorods and nanoparticles have been synthesized using a vapor-solid reaction path starting with carbon nanotube precursors. Their structures are studied using XRD, TEM, and HRSEM. Their superconducting properties of nanoparticles were also characterized using a SQUID magnetometer. For reactions at lower temperatures, NbC nanorods (10 - 20 nm) which replicate the precursor carbon nanotubes are observed. For reactions at higher temperature, coarsened NbC nanoparticles (100 - 500 nm) are observed which have spherical or faceted morphologies. A morphological Rayleigh instability can be applied as initiating the transition from NbC nanorod to nanoparticle morphologies. NbC nanoparticles with a little larger lattice parameter show a higher T_c than stoichiometric bulk NbC.