ELECTRICAL-CONDUCTIVITY, HALL-COEFFICIENT, AND MAGNETORESISTANCE IN BINARY CSCX AND TERNARY CSC24(C2H2)1.1 AND CSC24(C2H4)1.1

Electronic properties of binary and ternary cesium-graphite intercalation compounds, CsC(x) (60 greater-than-or-equal-to x greater-than-or-equal-to 24), CsC24(C2H2)1.1, and CsC24(C2H4)1.1 have been studied. Samples of CsC, were prepared from Grafoil, and ternary compounds CsC24(C2H2)1.1 and CsC24(C2H4)1.1 were derived from CsC24 by contacting it with C2H2 or C2H4 at 0-degrees-C. The in-plane electrical conductivity (sigma(a)), magnetoresistance (DELTArho/rho) and Hall coefficient (R(H)) of these compounds were measured at room temperature. For the binary compounds, sigma(a) was found to increase linearly with increasing concentration Cs/C, while DELTArho/rho and the absolute value of R(H) to decrease. For CsC24(C2H2)1.1, sigma(a) is lower and DELTArho/rho and the absolute value of R(H) are higher than those of host CsC24, but no appreciable differences are observed for CsC24(C2H4)1.1. Carrier densities n(e) and n(h), and mobilities mu(e) and mu(h), where e and h denote electrons and holes, respectively, were calculated on the basis of a classical two-carrier model. The calculation reveals that back-donation of conduction electrons to Cs ions takes place in CsC24(C2H2)1.1, but not in CsC24(C2H4)1.1.