Low-temperature growth of YBCO thin films by pulsed laser ablation in reducing environment

摘要

The effect of ambient gas on the preparation of YBa2Cu3Ox (YBCO) high-Tc superconducting thin films by pulsed laser ablation was explored in gas mixtures of argon+oxygen, argon+nitrous oxide, and nitrous oxide+oxygen. These experiments revealed that a reducing environment for the preparation of YBCO films enhances the film growth with the high temperature phase (trilayered perovskite YBCO) rather than the low temperature phase (cubic YBCO). This phenomenon is explained in terms of thermodynamic phase diagram. The effect of nitrous oxide on the thermodynamic phase diagram is far smaller than that of oxygen by a factor of two to three orders of magnitude.