Resistive superconducting transition and effects of atmospheric exposure in The intercalation superconductor Ax(C2H8N2)yFe2-ZzSe2 (A Li, Na)

We have succeeded in observing zero-resistivity in newly discovered intercalation superconductors Ax(C2H8N2)yFe2-zSe2 (A Li, Na) with T_c 45 K, using The sintered pellet samples. The electrical resistivity, ρ, in The normal state is metallic and T_c^onset defined in The ρ measurements, is as high as ∼ 57 K. We have also investigated effects of The atmospheric exposure in Li_x(C₂H₈N₂)_yFe_2-zSe₂. It has been found that both The crystal structure and superconductivity are maintained at least up to several days, indicating this material is comparatively resistant to The atmospheric exposure.