Effects of high magnetic field on the morphology of carbon nanotubes and selective synthesis of fullerenes

Carbon nanotubes and fullerenes were synthesized by arc discharge in a He gas atmosphere under a high magnetic field up to 10 T. Morphology and the yield of these nanotubes were investigated by scanning electron microscopy and transmission electron microscopy (TEM). The yield and type of fullerenes were also evaluated by ultraviolet visual spectroscopy. TEM images revealed that thin collapsed nanotubes having larger curvature were synthesized under a high magnetic field, in particular at 10 T. Furthermore, the ratio of C-70 to C-60 concentration was found to vary depending on the magnitude of the magnetic field during arc discharge. Based on these results, the effects of magnetic field on the synthesis of carbon nanotubes and fullerenes are discussed. (C) 1999 American Institute of Physics. [S0003-6951(99)04013-9].