2, Arizona State University, Tempe, Arizona, United States
3, NXP Semiconductors, Chandler, Arizona, United States
In this study, a low-fluorine solution route was developed for the fabrication of YBa2Cu3O7-x(YBCO) coated conductors. In this approach, the solution contains 20-30% of the fluorine of the traditional all-trifluoroacetate solution route. This enables high-speed production of much smoother YBCO films. We systematically investigated the influence of the fluorine content on the phase evolution and superconducting properties of the films. We found that a broad range of fluorine contents can be used to prepare thin high-quality YBCO films. In contrast, for thick YBCO films (with thicknesses over 1μm), F/Ba=2 (in the solution) is optimal to obtain high-Jc YBCO films. So, we used a solution with F/Ba=2. We also developed a deep UV light soaking technique to prepare YBCO films. Instead of thermal pyrolysis of the precursor film, we used UV light to decompose the precursor. This resulted in the constituent elements being uniformly distributed in the films, resulting in enhanced Jc. The addition of water vapor (during the UV irradiation) resulted in the formation of radical O*. This promoted the removal of carbon residue from the films, and further increased the Jc of the resulting YBCO films.