Magnetization measurements performed on amorphous carbon (aC) powder that contained a small amount of sulfur revealed traces of inhomogeneous superconductivity (SC) at T c=65 K. Thin films of granular aC-W composite obtained by Electron Beam Induced Deposition showed no sign of SC. However, SC at T c≈40 K was induced upon treating this film with sulfur at 250 °C for 24 hours. Although the superconducting volume fraction in both cases is very low, our results prove the necessity of sulfur for inducing SC in aC, and open new pathways to achieve high-temperature SC in the unique system of aC-based materials.
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Acknowledgements The research is supported in parts by the Israel Science Foundation (ISF, Bikura 459/09), the German-Israel DIP program and by the Klachky Foundation for Superconductivity. O.M. thanks for support from the Harry de Jur Chair of Applied Science.
- Amorphous carbon
- Localized superconductivity