Possible Superconductivity at 37K in Graphite-Sulphur Composite

Sulphur intercalated graphite composites with diamagnetic transitions at 6.7 and 37K are prepared. The magnetization hysteresis loops (MHL), x-ray diffraction (XRD) patterns, and resistance have been measured. From the MHL, a slight superconducting-like penetration process is observed at 15K in the low field region. The XRD shows no large difference from the mixture of graphite and sulphur indicating that the volume of the superconducting phase (if any) is very small. The temperature dependence of resistance shows a typical semi-conducting behaviour with a saturation in the low-temperature region. This saturation is either induced by the delocalization of conducting electrons or by possible superconductivity in this system.