Structural and Transport Studies for Ternary Graphite Intercalated Phases (CoCl2, AlCl3)

Abstract

Metal dihalide low-volatility is the major characteristic slowing down their intercalation into graphite (GICs: graphite intercalation compounds). An original synthesis using volatile heterocomplexes between metal dihalide (CoCl2) and gaseous dimer Al2Cl6 increases strickingly CoCl2 intercalation rate but entails cointercalation of significative amount of AlCl3 in the compounds MGICs (mixture graphite intercalation compounds). Structural studies along c-axis, in plane and out the plane (3 D stacking) display a similar behaviour as in the CoCl2 containing binary compounds. Microstructural studies confirm the separation of CoCl2 and AlCl3 in distinct domains. Other ternary phases with alternate CoCl2 and AlCl3 layers and characterized by a similar AlCl3/CoCl2 ratio can be obtained using biintercalation method: (GBICs: graphite biintercalation compounds). X-Ray diffraction shows that the biintercalation involves a complete lost of correlations in the successive CoCl2 or graphite layers. Transport studies of ternary phases (MGICs and GBICs) display an anomalous behaviour as T is lowered below the magnetic ordering temperature Tc especially for in plane resistivity.