Electrical Properties of Graphite Nitrates Perpendicular to the Layers

An improved method for making measurements normal to the layers in lamellar compounds is described. This preserves good contact under moderate pressures, while permitting unobstructed expansion of the specimen during intercalation, or changes of temperature. As a particular example detailed measurements are reported on the electrical resistance of graphite nitrates for temperatures traversing the thermal transformation at about 252 K. Magneto-resistance data have also been obtained. Mechanisms of charge transport perpendicular to the layers are discussed in relation to present findings for graphite nitrates. From the data available, extrinsic conduction paths would appear to make substantial contributions to the total c-axis conductivity.