SUPERCONDUCTING SINGLE-CRYSTALS OF TAC ENCAPSULATED IN CARBON NANOTUBES

The synthesis and electron microscopic studies of TaC single crystals encapsulated in carbon nanotubes are reported. The crystal structure is the NaCl type with the lattice parameter a0=4.455+/-0.003 angstrom. The typical crystalline size is approximately 7 nm. The epitaxial growth of carbon nanotube on the {100} plane of the TaC single crystal is observed. The statistical growth model is adequate for explaining the crystalline-particle size distribution of the encapsulated crystals. Magnetic susceptibility measurements show a superconducting transition at 10.0 K, which is the expected critical temperature for the bulk TaC having the highest carbon composition.