Thermal and elastic properties of hard carbon

In the present study are given thermal conductivity and elastic measurements of hard and conducting form of carbon obtained from C-60 fullerene. Structural investigations provide data on the mesoscopic structural inhomogeneities that are important for the understanding of thermal and elastic properties in the material. Thermal conductivity exhibits characteristic low temperature features of a fractal structure, with a cubic behaviour on lowest temperatures due to the occurrence of boundary effects. At higher temperatures, a linear temperature dependence of the thermal conductivity is observed. The sound velocity decreases linearly in the same temperature range. Both linear regimes are characteristic of disordered structures, and are analysed using theoretical models developed for fractal and disordered structures.