Resistive superconducting transition and effects of atmospheric exposure in the intercalation superconductor Ax(C2H8N2)yFe2- zSe2 (A = Li, Na)

Abstract

We have succeeded in observing zero-resistivity in newly discovered\nintercalation superconductors Ax(C2H8N2)yFe2-zSe2 (A = Li, Na) with Tc = 45 K,\nusing the sintered pellet samples. The electrical resistivity, \\r{ho}, in the\nnormal state is metallic and Tconset defined in the $\\rho$ measurements, is as\nhigh as ~ 57 K. We have also investigated effects of the atmospheric exposure\nin Lix(C2H8N2)yFe2-zSe2. It has been found that both the crystal structure and\nsuperconductivity are maintained at least up to several days, indicating this\nmaterial is comparatively resistant to the atmospheric exposure.\n