ABSTRACT
The behavior of the c-axis resistivity pc(7) is qualitatively different from the in-plane resistivity, as shown in Fig. 17 for C6 4F and CXHF2 samples based on
Figure 14 Change in the electrical conductivity with time of CXF fiber inter calation compounds in air: (a) PAN-based fiber C10.iF, (b) pitch-based fiber C9 7F, and (c) vapor-grown carbon fiber C92F. (From Ref. 9.)
Figure 15 Differential thermal analysis (DTA) and thermogravimetric (TG) curves of CXF intercalation compounds in a nitrogen atmosphere (heating rate 10°C min-1) in (a) PAN-based fiber C71F, (b) pitch-based fiber C99F, and (c) vapor-grown carbon fiber C95F. (From Ref. 9.)
HOPG [27]. This behavior has been tentatively explained in terms of an im purity-assisted hopping mechanism at low temperature and a thermally excited hopping mechanism at high temperature [27]. The experimental results for the CxHF2 sample in Fig. 17 are in general agreement with the results of Vaknin et al. [26]. More generally, the behavior of the c-axis resistivity (or conductivity) in GICs is not understood, despite the various theoretical models that have been proposed.
