X-ray diffraction and magnetic susceptibility of sodium fullerides NaxC60 Original Research Article

The X-ray diffraction (XRD), magnetic susceptibility and electron spin resonance (ESR) measurements have been carried out for NaxC60. The XRD profiles with x<4 can be assigned to a face-centered cubic (fcc) lattice, while those with 4≦x to a hexagonal one. The temperature dependence of magnetic susceptibility χ for NaxC60 using SQUID was fitted to the Curie law, and estimated temperature-independent component χ0. The composition x dependence of the χ0 for NaxC60 shows two maxima at around x=3 and x=10, and minimum at x=6. The absence of Pauli contribution at x=6 was confirmed using ESR. A trace of superconducting transition at 14 K has been found for some NaxC60 specimens with 8