Conductive Polymer / High-Tc Superconductor Assemblies

The preparation of a hybrid conducting polymer/high-temperature superconductor device consisting of a polypyrrole coated YBa2Cu3O7-δ microbridge is reported. Electrochemical techniques are exploited to alter the oxidation state of the polymer and, in doing so, it is found for the first time that superconductivity can be modulated in a controllable and reproducible fashion by a polymer layer. Whereas the neutral (insulating) polypyrrole only slightly influences the electrical properties of the underlying YBa2Cu3O7-δfilm, the oxidized (conductive) polymer depresses Tc by up to 15K. Thus, a new type of molecular switch for controlling superconductivity is demonstrated.