Investigation of High-Tc Superconductivity in Carbon Nanotubes

摘要

The magnetization of thin films of carrier-doped CNTs was measured. Increase in transition temperature Tc to 28 K was obtained by annealing the sample at 1473 K, which is higher than previous conditions. However, diamagnetism in zero-field-cooled and field-cooled regimes in raw data was not observed owing to positive background magnetization arising from residual impurities in CNTs. Hence, Meissner effect was not concluded in the present experiments. It is expected that further purification of the CNTs must realize confirmation of Tc = 28 K, as Meissner effect, and it may make Tc > 30K possible in the near future.