PREPARATION OF ALKALINE-METAL-DOPED C60 SUPERCONDUCTING FILM AND ITS STABILIZATION IN AIR WITH PROTECTIVE COATINGS

Preparation conditions of C60 film were studied by varying substrates, substrate temperature and the rate of evaporation. Crystalline C60 th in films were prepared on GaAs(100) at the substrate temperature of 10 0-degrees-C in order to obtain superconductors by alkaline metal dopin g. The Rb/Cs-doped film showed a superconducting transition with T(c)( onset) = 24 +/- 3 K and T(c)(zero) = 8 K. The composition of the super conducting film was measured by micro-Auger electron spectroscopy. Air stability of Rb3C60 superconducting film with protective coatings app lied was studied. A Si protective film maintained superconductivity fo r 220 min in air. In addition a Si/Al protective coatings maintained s uperconductivity for 8 h.