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M. Saint Jean Groupe de Physique des Solides, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris Cedex 05, France (Received 11 June 1987; accepted 8 October 1987) Part I of this study has shown that first stage AsF 5 intercalated graphite samples can be classified into two types of compounds, depending upon the nature of the structural modifications they undergo upon lowering the temperature from 295 to 4.2 K. These structural changes are related to demixing of the species contained within the intercalate resulting in the formation of phases rich in AsF 5 , AsF6~ — AsF 5 , or AsF 3 depending on the degree to which the AsF 5 has been converted into AsF6~ and AsF 3 . Resistivity studies have been carried out in the basal plane [pa (T)] and along the c axis [pc (T) ]. The type 1 compounds, in which the AsF 5 has undergone little conversion, manifest apa (T) transition related to the incommensurate-tocommensurate (/-» C) transformation of the AsF 5 in-plane unit cell and a rapid, structureless 300 to ~ 200 K decrease inpc (T). The type 2 compounds involving a greater degree of conversion of AsF 5 into AsF 3 and AsF6~ yield more complex/?c (7") behavior from 300 to 200 K attributed to the more involved ordering phenomena; no anomalies are seen inp o (T). In the case of the stage 2 compounds, changes mpc (T) are seen down to lower temperatures in accord with structural dataindicatingadownshiftofthe/->C transformation by ~ 7 0 K . The transport results are discussed in the light of the crystallographic data and the low-temperature results are analyzed within the framework of proposed conductivity models.

I. INTRODUCTION The work to be discussed here follows that presented in the preceding article' and in an earlier publication.2 In the former we were able to interpret quite fully the diffraction results indicative of the structural order and changes taking place within these materials over the 4.2-295 K temperature (T) range. In Ref. 2 we presented the first results relative to the temperature dependence of the electrical resistivity in the basal plane [Pa (T) ] and along the c axis [pc (T) ] and thus to the anisotropy A (T) [ = pc (T) / pa (T) ]. The stage 1 compounds were shown to be of fixed dimensionality below ~ 180 K; the anisotropy was greater in stage 2 products, attaining ~ 3 X 106 at 4.2 K. The existence of AsF 5 - and AsF6~-rich phases was postulated, and we associated the pa (T) anomalies sometimes found, as well as the "quench" effects with the scattering due to the interdomain structure of the heterogeneous intercalate. In the present work we strive to more fully correlate the crystallo-chemical and transport data and to furnish responses to some of the questions posed in Ref. 2 conJ. Mater. Res. 3 (1), Jan/Feb 1988

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cerning the origins of the pa (T) anomaly and the structure seen in thepc(T) curves. A considerable amount of literature exists concerning the electronic properties of these materials, some of which can be found in Refs. 2—4 and references therein. Various prob