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JETP Letters

, Volume 107, Issue 9, pp 577–578 | Cite as

Superconducting Sweet-Spot in Microcrystalline Graphite Revealed by Point-Contact Spectroscopy

  • F. Arnold
  • J. Nyéki
  • J. Saunders
Condensed Matter

Abstract

In this letter, we describe the observation of a magnetic field dependent electronic gap, suggestive of local superconductivity, in the point-contact spectrum of microcrystalline graphite. Magnetic field dependent point-contact spectroscopy has been carried out at a temperature of 1.8 K using an etched aluminum tip. At zero field, a gap structure in the differential conductance is observed, showing a gap of Δ = 4.2 meV. On applying magnetic fields of up to 500 mT, this gap gradually closes, following the theoretical prediction by Ginzburg and Landau for a fully flux-penetrated superconductor. By applying BCS-theory, we infer a critical superconducting temperature of 14 K.

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Copyright information

© Pleiades Publishing, Inc. 2018

Authors and Affiliations

  1. 1.Royal HollowayUniversity of LondonEgham Hill, EghamUnited Kingdom

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