Preparation and superconductivity of potassium-doped fullerene nanowhiskers

Abstract Superconductivity at 17 K was observed in a potassium (K)-doped fullerene nanowhisker (K-C60NW). The superconducting volume fraction of a full shielding volume was as high as 80% in the nominal composition of K3.3C60NW, while that of K-doped fullerene powder was less than 1% under the same heating condition at 200 °C. We report the superconducting behaviors of our newly synthesized K3.3C60NWs, such as the applied field dependence of magnetization and the critical current density of 3 × 105 A/cm2 at 5 K under 50 kOe, in comparison to those of K-doped fullerene powders.