ALKALI-METAL DOPING OF LANGMUIR-BLODGETT-FILMS OF C-60 STUDIED BY ESR

Various doping methods were used in order to realize the charge transf er between C-60 molecules and alkali-metal atoms in the Langmuir-Blodg ett structure. ESR measurements have clearly indicated the charge tran sfer the samples heated with RbN3 powder. The development of the metal lic region in these films, possibly in the form of o-Rb1C60, has been indicated, for the first time, by the obtained Pauli-like spin suscept ibility and the Elliott-like ESR linewidth. Furthermore, hysteresis wa s observed in the low-magnetic-field microwave absorption signal (LFS) for a sample, showing the appearance of the superconducting phase wit h T-c approximate to 23 K in the sample tube.