Electrical conductivity studies of a pure C₆₀single crystal

Single crystals free from solvent up to millimetre size were grown. The temperature dependence of the electrical conductivity of a C 60 single crystal was reported. A sharp decrease in conductivity related to the phase transition at 251 K was confirmed. A drop in the activation energy of around 274 K was observed for the first time. This activation energy drop suggests that the rotational dynamics of the C 60 molecule above 251 K are more complex than the uncorrelated diffusion reported by Neumann et al.