Original synthesis route of bulk binary superconducting graphite intercalation compounds with strontium, barium and ytterbium

Abstract

Thanks to its lamellar structure, graphite can host various chemical species between its interplanar spaces to form Graphite Intercalation Compounds (GIC). Intercalation of metals into graphite can lead to remarkable modifications of the physical properties of the sample with respect to pristine graphite as for instance superconductivity. In this paper, we report attempts made to intercalate strontium, barium and ytterbium into graphite, using a recent method involving a LiCl–KCl molten salt as a reaction medium. Resulting samples are characterized regarding their structure and chemical composition. We reveal the obtaining of bulk SrC₆ and BaC₆ and a superficial intercalation of ytterbium leading to superconducting YbC₆ domains only, as confirmed by dc-magnetization measurements.