  We have observed periodically repeated steps in the resistance vs.
temperature characteristics of doped Highly Oriented Pyrolytic Graphite and
exfoliated doped multi-layer graphene. The observations consist of a series of
regularly spaced steps in the resistance vs. temperature curves. The lowest
step is observed at a temperature of from 50 to 60 K. Additional steps are
observed at multiples of that basic temperature with the highest step
temperature being at approximately 270 K. Quenching by a modest applied
magnetic field has been observed. The sizes and widths of the observed steps
appear to vary and may be related to some sort of aggregation reminiscent of
flux vortex pinning. An additional argon ion implantation at reduced energy was
done to see if additional defects in the material would yield additional
structure. This was observed to yield much sharper resistance steps at
temperatures in excess of 200 K in thin exfoliated peels from the implanted
surface of the sample and would support the possibility of the steps being
related to pancake vortex pinning in a layered superconductor. Unfortunately,
as yet, there has been no direct measurement of either the superconducting
energy gap nor has a definitive Meissner effect been observed.
