title: Synthesis and superconducting properties of CaC6.
abstract: Among the superconducting graphite intercalation compounds, CaC6exhibits the highest critical temperatureTc=11.5 K. Bulk samples of CaC6are obtained by immersing highly oriented pyrographite pieces in a well-chosen liquid Li-Ca alloy for 10 days at 350 °C. The crystal structure of CaC6belongs to the [Formula: see text] space group. In order to study the superconducting properties of CaC6, magnetisation was measured as a function of temperature and direction of magnetic field applied parallel or perpendicular to thec-axis. Meissner effect was evidenced, as well as a type II superconducting behaviour and a small anisotropy. In agreement with calculations, experimental results obtained from various techniques suggest that a classical electron-phonon mechanism is responsible for the superconductivity of CaC6. Application of high pressure increases theTcup to 15.1 K at 8 GPa.
authors.affiliation: Laboratoire de Chimie du Solide Minéral-UMR 7555, Nancy Université, Université Henri Poincaré, BP 239, 54506 Vandœuvre-lès-Nancy Cedex, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Emery
authors.affiliation: Laboratoire de Chimie du Solide Minéral-UMR 7555, Nancy Université, Université Henri Poincaré, BP 239, 54506 Vandœuvre-lès-Nancy Cedex, France.
authors.forename: Claire
authors.initials: C
authors.lastname: Hérold
authors.affiliation: Laboratoire de Chimie du Solide Minéral-UMR 7555, Nancy Université, Université Henri Poincaré, BP 239, 54506 Vandœuvre-lès-Nancy Cedex, France.
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Marêché
authors.affiliation: Laboratoire de Chimie du Solide Minéral-UMR 7555, Nancy Université, Université Henri Poincaré, BP 239, 54506 Vandœuvre-lès-Nancy Cedex, France; Ecole Européenne d'Ingénieurs en Génie des Matériaux, Institut National Polyechnique de Lorraine, 6 rue Bastien Lepage, BP 630, 54010 Nancy Cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lagrange
keywords: crystal structure; graphite intercalation compound; superconductivity; synthesis; x-ray diffraction