This work deals with the intrinsic and extrinsic properties of the graphene
layers inside the graphite structure, in particular the influence of defects
and interfaces. We discuss the evidence for ballistic transport found in
mesoscopic graphite samples and the possibility to obtain the intrinsic carrier
density of graphite, without the need of free parameters or arbitrary
assumptions. The influence of internal interfaces on the transport properties
of bulk graphite is described in detail. We show that in specially prepared
multigraphene samples the transport properties show clear signs for the
existence of granular superconductivity within the graphite interfaces. We
argue that the superconducting-insulator or metal-insulator transition (MIT)
reported in the literature for bulk graphite is not intrinsic of the graphite
structure but it is due to the influence of these interfaces. Current-Voltage
characteristics curves reveal Josephson-like behavior at the interfaces with
superconducting critical temperatures above 150K.Comment: 26 pages, 15 figures. To be published in "Graphene, Book 2" by
Intech, Open Access Publisher 2011, ISBN: 979-953-307-180-
