Can Doping Graphite Trigger Room Temperature Superconductivity? Evidence for Granular High‐Temperature Superconductivity in Water‐Treated Graphite Powder

Abstract

Granular superconductivity in powders of small graphite grains (several tens of micrometers) is demonstrated after treatment with pure water. The temperature, magnetic field and time dependence of the magnetic moment of the treated graphite powder provides evidence for the existence of superconducting vortices with some similarities to high-temperature granular superconducting oxides but even at temperatures above 300 K. Room temperature superconductivity in doped graphite or at its interfaces appears to be possible.

Stacking-Dependent Electronic Structure of Trilayer Graphene Resolved by Nanospot Angle-Resolved Photoemission Spectroscopy

“…flat band high temperature superconductivity, 25,26,28 various magnetic orders 29 etc. Under an applied magnetic field, a Lifshitz transition induced by trigonal warping in rhombohedral trilayer graphene has been reported.…”

Evidence for room temperature superconductivity at graphite interfaces

“…Similar TH measurements of the n-heptane treated graphite powder with superconducting like field hysteresis (as in [7,8]) show a completely different behavior. The influence of temperature on the TH curves is not monotonous in the whole applied field, see the crossing of the curves at ∼ 0.3 T in Fig.…”

“…RWA/T from SGL Carbon GmbH (Werk Ringsdorff, Germany) with very low impurity concentration (e.g., Fe < 0.19 µg/g). Further characterization of this graphite powder and the influence of water on its magnetization was thoroughly reported in [7]. In this study we found that if we follow the same procedure to treat the graphite powder with nheptane as was done with water, i.e.…”

“…However, after a treatment with water [7] or n-heptane (following the work in [11]) a clear irreversibility in field and in temperature is observed. As example, Fig.…”

“…The field hysteresis loops, the hysteresis in temperature, i.e. difference between the magnetization at field cooled (FC) and zero field cooled (ZFC) [7], suggest the existence of granular superconductivity at certain regions formed after the liquid treatment. Because a similar behavior is observed in graphite samples with The difference between FC and ZFC curves ∆m as a function of applied field at different temperatures for the: (a) bulk HOPG sample (field applied parallel to the graphene planes), which magnetization shows a ferromagnetic hysteresis loop and (b) a n-heptane-treated graphite powder, which shows a field hysteresis similar to that of water treated graphite powder, see Fig.…”