Modification on the surface of superconducting YBa2Cu3O7−x films by microwave plasma-enhanced pulsed laser deposition

Abstract

Superconducting YBa2Cu3O7−x films having smooth surfaces were successfully synthesized by a microwave plasma-enhanced pulsed laser deposition (PEPLD) process. Particulates that frequently occurred in films grown by the conventional PLD process were effectively eliminated. The films were epitaxial-like. The c-axis was perpendicular to the films’ surface, the a and b axes were aligned in the films’ plane, and the onset and zero of the transition temperature were at Tc=90 K and Tc0=86 K, respectively. Optical emission spectroscopy indicated that the presence of oxygen plasma not only reexcited the laser-induced species via the collision process, but also produced abundant atomic oxygen in PEPLD process. The surface reaction kinetics for the formation of the thin-film process was thus greatly enhanced, which substantially improved the thin-film quality.