Preparation and Characterization of YBa₂Cu₃O_7-δ/Polypyrrole Bilayer Structures

Electrochemical techniques are exploited to fabricate conductive polymer/high-T_c superconductor bilayer structures. Scanning electron microscopy, atomic force microscopy, and electrochemical techniques are utilized to characterize the electrodeposition of polypyrrole layers grown onto YBa₂Cu₃O_7-δ films. In such hybrid polymer/ superconductor systems, it is found that, when the polymer is oxidized to its conductive state, the transition temperature (T_c) and critical currents (J_c) of the underlying superconductor film are suppressed. Reversible modulations of the transition temperatures of up to 50 K are noted for these structures. Upon reduction of the conductive polymer layer back to its nonconductive form, both T_c and J_c are found to return to values close to those acquired for the underivatized YBa₂Cu₃O_7-δ film.