Abstract
Among graphite intercalation compounds, the CaC6 binary phase exhibits superconducting properties with the highest critical temperature of 11.5 K. The samples are synthesised using a liquid-solid method allowing the preparation of pure bulk samples, auspicious for crystallographic and magnetic measurements. Thecrystal structure of CaC6 was entirely specified, this compound crystallises in the Om space group.The magnetic properties of this phase were studied with a magnetic field successively applied parallel and perpendicular to the graphene sheets. The magnetic phase diagram indicates that the CaC6 binary compound is a type II superconducting material slightly anisotropic in spite of its lamellar structure. The in-plane magnetic penetration depth measurements show a clear exponential behaviour at low temperature, consistent with an s-wave symmetry of the gap function, well fitted by the standard BCS theory in the dirty limit.
