%0 Journal Article %@ 1098-0121 %A Smith, RP %A Kusmartseva, A %A Ko, YTC %A Saxena, SS %A Akrap, A %A Forro, L %A Laad, M %A Weller, TE %A Ellerby, M %A Skipper, NT %D 2006 %F discovery:9476 %I AMER PHYSICAL SOC %J PHYS REV B %K GRAPHITE-INTERCALATION COMPOUNDS, STATE %N 2 %P ? - ? %T Pressure dependence of the superconducting transition temperature in C6Yb and C6Ca %U https://discovery.ucl.ac.uk/id/eprint/9476/ %V 74 %X We have studied the evolution, with hydrostatic pressure, of the recently-discovered superconductivity in the graphite intercalation compounds C6Yb and C6Ca. We present pressure-temperature phase diagrams, for both superconductors, established by electrical transport and magnetization measurements. In the range 0-1.2 GPa the superconducting transition temperature increases linearly with pressure in both materials with dT(c)/dP=+0.37 +/- 0.01 and +0.50 +/- 0.05 K/GPa for C6Yb and C6Ca, respectively. The transition temperature in C6Yb, which has been measured up to 2.3 GPa, reaches a peak at around 1.8 GPa and then starts to drop. We also discuss how this pressure dependence may be explained within a plasmon pairing mechanism. (c) 2006 American Institute of Physics.