One-dimensional metallofullerene crystal generated inside single-walled carbon nanotubes

Electron microscope imaging for gadolinium metallofullerenes encapsulating in single-wall carbon nanotubes [(Gd@Cp-82)(n)@SWNTs] identifies the single Gd atom encaged in each. The intermolecular distance between Gd@C-82 is extremely regular, regarding the chains of Gd@C-82 as novel one-dimensional crystals. Chemical state analysis of Gd atoms suggests evidence for charge transfer from Gd to either a fullerene cage or a nanotube. The slopes of the temperature dependence of electric resistance for the matlike films of (Gd@C-82)(n) @SWNTs and (C-60)(n) @ SWNTs are much steeper than that for empty SWNTs, suggesting the electron scattering due to the electrostatic potential from inside fullerenes playing an important role.