c-axis resistivity of graphite intercalation compounds

Abstract

The c-axis resistivity of stage-2, 3, 4, 5, 6, 7, and 9 graphite intercalation compounds (GICs) has been measured in the temperature range between 4.2 and 300 K with and without an external magnetic field along the c-axis. In these compounds the c-axis conduction is dominated by the in-plane conduction because of the highly anisotropic resistivity. The temperature dependence of strongly depends on the stage number. The stage-2 and 3 GICs show a metallic behaviour: increasing with increasing temperature. The logarithmic behaviour in is observed in a limited temperature range for stages 5 and 6, and negative longitudinal magnetoresistance is observed for stages 3 to 7, indicating that the two-dimensional weak localization effect may occur mainly in the interior graphite layers with a small charge transfer. The c-axis resistivity of stage-3 to 9 GICs shows a unusual thermal hysteresis in the temperature range between 180 and 240 K. It has two local minima at critical temperatures - 210 K) and (= 223 - 231 K) depending on the stage number. The carriers in the bounding graphite layers with a large charge transfer are scattered by enhanced fluctuations due to electric dipole moments of molecules. There may occur a two-dimensional- (2D-) like dipole ordered phase below and a 3D-like dipole ordered phase below .

The Role of Chemistry in Graphene Doping for Carbon-Based Electronics

“…A common graphitic intercalate used recently as a dopant in carbon-based electronics is composed of antimony−chloride molecular complexes. , The parent compound of this intercalate is the strong Lewis acid SbCl 5 . In graphite, the fluidlike intercalate layer is composed of a mixture of open- and closed-shell antimony species including SbCl 3 , SbCl 4 , and SbCl 6 . Antimony can accommodate such diverse bonding configurations because of its ability to form sp 3 d n hybridized orbitals, where n = 0,1,2.…”

“…In graphite, the fluidlike intercalate layer is composed of a mixture of open-and closed-shell antimony species including SbCl 3 , SbCl 4 , and SbCl 6 . 57 Antimony can accommodate such diverse bonding configurations because of its ability to form sp 3 d n hybridized orbitals, where n = 0,1,2. We track in a clean fashion the emergence of open-shell entities by performing a 30 ps room temperature simulation of an SbCl 5 :C 14 bilayer system (see the Supporting Information video 1).…”

Heat Capacity Studies of Nanocrystalline Magnetite (Fe3O4)

“…Recent studies by Suzuki et al indicate that nanocrystalline magnetite may exhibit a superspin-glass phase below a freezing temperature of T f = 30.6 ± 1.6 K. Heat capacity models of the transition from a paramagnet (or superparamagnet) to a spin glass display a broad anomaly at the transition temperature, , and the low-temperature limiting form of the spin-glass heat capacity can be approximated by C = γ T + B 2 T 2 . Low-temperature heat capacity measurements can help discern between superparamagnetic and spin-glass behavior and help remove some uncertainty in the understanding of magnetic behavior in nanocrystalline magnetite.…”

Transport and NMR study of the scandium boron carbide compoundSc2B1.1C

“…Previously such 2D weak localization effects have appeared a number of times in similar graphite intercalation compound systems. [11][12][13][14][15][16][17] Actually some of these GIC's were judged to be good model systems for studying 2D weak localization. 13,17 The magnetic-field dependence of the resistivity at 5, 20, and 100 K was measured.…”