$c$-axis electrical resistivity was measured from 1.5 to 300 K on the acceptor-type Sb${\mathrm{Cl}}_5$-graphite intercalation compounds of stages 1-6 and 10. The resistivity of the compounds is up to an order of magnitude larger (${10}^{-3\mathrm{}}$-${10}^{-2\mathrm{}}$ Ω m) than that of the parent highly-oriented pyrolytic graphite material, indicating that the mean free path is comparable to an atomic spacing. In spite of this large resistivity an entirely metallic temperature dependence of resistivity is observed for stages 1-3. Higher-stage compounds show metallic character only at high temperatures; as the temperature decreases one observes a crossover to an activated dependence of the resistivity. A model, based on defect-mediated short-circuiting channels, is proposed in order to reconcile the metallic dependence with the large $c$-axis resistivities observed in these compounds.

• Received 16 June 1982

DOI:https://doi.org/10.1103/PhysRevB.27.2477