Low-temperature thermal expansion of fullerite C60 alloyed with argon and neon

The linear thermal expansion of compacted fullerite C-60 alloyed with argon (ArxC60) and neon (NexC60) are investigated by a dilatometric method. The experimental temperature is 2-12 K. In the same temperature interval the thermal expansion of ArxC60 and NexC60 are examined after partial desaturation of the gases from fullerite. It is found that Ar and Ne alloying affects the temperature dependence of the thermal expansion coefficient of C-60 quite appreciably. The libration and translation contributions to the thermal expansion of pure C-60 are separated. The experimental results on the thermal expansion are used to obtain the Debye temperature of pure C-60. The effects observed are tentatively interpreted. (C) 2001 American Institute of Physics.