Transverse magnetoresistance in FeCl3 GIC

GIC-FeCl3 samples were prepared from a host matrix of highly oriented pyrolytic graphite using the two-zone phase growth method. The stage index, n, was determined by means of the (0 0 l) X-ray diffraction peaks from a θ-2θ scan at room temperature. Specimens of well-staged GIC-FeCl3 with n= 1, 3, 4, 5, 6 and 11 were selected. The transverse resistivity ρ(H) was determined with the magnetic field H applied perpendicularly to the c-axis, whereas the electrical current flowed in the c-axis direction. The transverse magnetoresistance, defined as [ρ(H) − ρ(0)] /ρ(0), was obtained for the fixed values of the temperature T=4.2 K and T= 300 K, at H=40 kG, for the various samples with different stage indices. We further report the magnetoresistance, at T=4.2 K, as a function of H in the range 0 ≤ H ≤ 40 kG for the different values of the stage index. No agreement could be obtained with predictions based on band models for two or more bands. This seems to indicate a thermally activated hopping conduction mechanism as a possible alternative to lead to explanations of the observed behavior of the transverse magnetoresistance.