Observation of bulk superconductivity in [formula presented] and [formula presented] powder and single crystals

Poly- and single-crystalline [Formula presented] has been successfully intercalated with [Formula presented] and [Formula presented] as confirmed by x-ray diffraction and thermogravimetric analysis. Resistivity, magnetic susceptibility, and specific heat measurements show bulk superconductivity with [Formula presented] close to 5 K in both cases. The substitution of deuterium for hydrogen has an effect on [Formula presented] of less than 0.2 K. Investigation of the resistivity anisotropy of [Formula presented] single crystals shows (a) almost zero resistivity below [Formula presented], and (b) an abrupt upturn at [Formula presented] in both the [Formula presented] plane and the [Formula presented] direction. The implications of our results on the possible superconducting mechanism will be discussed.