Observation of a Non-Magnetic Impurity Effect in the Organic Superconductor (TMTSF)_(2)ClO_(4)

摘要

We report a non-magnetic impurity effect on the superconductivity observed in (TMTSF)_(2)ClO_(4). By varying the sample cooling rate in the vicinity of an anion ordering transition at T_(AO) velence 24 K, we can systematically control the amount of disorder in the sample. We then use dc transport and microwave periodic orbit resonance measurements (closely related to cyclotron resonance) to determine the critical temperature T_(c) and the transport scattering time tau. We find a simple relationship between the two quantities, which strongly suggests that the superconductivity is suppressed by non-magnetic impurities, thus supporting the scenario for unconventional p-wave superconductivity in this material.