Structure and properties of a fulleride Sm6C60

A fulleride Sm6C60 has been synthesized using the high-temperature solid-state reaction. The Rietveld refinement on high-resolution synchrotron x-ray powder-diffraction data shows that Sm6C60 is isostructural with body-centered-cubic A(6)C(60) (A = K, Ba). The Raman spectrum of Sm6C60 is similar to that of Ba6C60 and the frequencies of two A, modes in Sm6C60 are nearly the same as that of Ba6C60, suggesting that Sm is divalent and hybridization between C-60 molecules and the Sm atom could exist in Sm6C60. Resistivity measurement shows a weak T-linear behavior above 180 K; the transport at low temperature is mainly dominated by granular-metal theory. [S0163-1829(99)02533-3].