  Following our previous investigations on superconductivity in amorphous
carbon (aC) based systems; we have prepared thin composite aC-W films using
electron-beam induced deposition. The films did not show any sign for
superconductivity above 5 K. However, local, non-percolative, superconductivity
emerged at Tc = 34.4 K after treatment with sulfur at 250 C for 24 hours. The
superconducting features in the magnetization curves were by far sharper
compared to our previous results, and the shielding fraction increased by about
an order of magnitude. Our data suggest that pairing and localized
superconductivity take place in the aC-S regions, whereas phase coherence,
assisted by the W inclusions, was enhanced compared to our previous samples,
yet still not to the degree of achieving global phase-coherence and percolating
superconductivity.
