  The temperature dependent frequency shifts of the Raman active G-band have
recently been measured by R.Walter et al. for single-walled carbon nanotubes
containing different concentrations of the magnetic impurity Ni:Co. These Raman
data can be quantitatively explained by magnetic pair-breaking effect on a
superconductor with a mean-field transition temperature T_c0 of 645 K, in
excellent agreement with independent electrical transport and single-particle
tunneling data. We suggest that such high-T_c superconductivity might arise
from the pairing interaction mediated mainly by undamped acoustic plasmons in a
quasi-one-dimensional electronic system.
