The intercalation of Au, Ag or In, from an electrode and into polycrystalline thin films, was studied by performing time-dependent and space-resolved conductivity measurements under controlled O-free atmospheres using various temperatures and electric fields. The time versus resistivity behavior was explained in terms of the electric-field induced diffusion of metal ions from the electrode and into the interstitial positions of the fullerenes; with the local formation of MxC60 and MxC70 phases. A comparison of the resistivity behaviours of the thin films showed that the process was sensitive to the electronic level structure of the fullerene molecules.

Field-Induced Diffusion of Gold and Related Phase Transformations in the C60 and C70 Fullerenes. L.Firlej, N.Kirova, A.Zahab: Physical Review B, 1999, 59[24], 16028-32