ELECTRICAL TRANSPORT PROPERTIES OF LOW-STAGE ASF5-INTERCALATED GRAPHITE

The in-plane resistivity of stage 1 and stage 2 AsF5-graphite intercalation compounds was measured using a contactless r.f. eddy current technique from 1.6 to 290 K. The magnetoresistance of a stage 1 compound was similarly measured from 4.2 K to 290 K. The low temperature stage 2 resistivity data show a well-defined intermediate ∞ ∝T2 region in addition to the usual ∞ ∝T high temperature region, in qualitative agreement with the Kukkonen theory and indicative of a small, elongated cylindrical Fermi surface. Stage 2 resistivity data also show, for the first time in a graphite-acceptor compound, an apparent low temperature phase transition at ≈ 21 K. Magnetoresistance data were used to determine a stage 1 carrier concentration of ≈ 9×1020 holes cm-3. Resistive anomalies were observed at ≈ 200 K and ≈ 220 K for stage 1 and stage 2 compounds, respectively. © 1979 Chapman and Hall Ltd.