|
VOLUME 107 (2018) | ISSUE 9 |
PAGE 604
|
Superconducting sweet-spot in microcrystalline graphite revealed by point-contact spectroscopy
F. Arnold, J. Nyéki, J. Saunders
Royal Holloway, University of London, Egham Hill, TW20 0EX, Egham, United Kingdom
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 micro-crystalline graphite. Magnetic field
dependent point-contact spectroscopy was carried out at a temperature of
using an etched aluminium 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.
|
|