Synthesis, structure, and transport properties of novel fullerides A(3)C(70) (A = Ba and Sm)

A series of new stable fullerides A(3)C(70) (A = Smr Ba) has been synthesiz ed using solid-state reactions. The structure of Sm3C70 has been identified to be monoclinic by simulation of synchrotron powder diffraction data. The structure of Ba3C70 is derived from the A15 structure adopted by Ba3C60. T he low symmetry relative to C-60 fullerides could be an important factor in the absence of superconductivity in C-70 fullerides. The electronic transp ort can be explained by a variable-range hopping mechanism for A3C70 (A = B a, Sm) samples, while the transport for SmxC70 (x > 3) samples appears to b e dominated by weak localization (WL) theory.