High Critical Current Density of YBa2Cu3O7-x Superconducting Films Prepared through a DUV-assisted Solution Deposition Process.

Yuanqing Chen,Wenhuan Huang,Lingwei Li,Xinni Tang,Wen Huo,Gaoyang Zhao,Jiqiang Jia,Weibai Bian,Na Li,Caiyin You

doi:10.1038/srep38257

Abstract

Although the solution deposition of YBa2Cu3O7−x (YBCO) superconducting films is cost effective and capable of large-scale production, further improvements in their superconductivity are necessary. In this study, a deep UV (DUV) irradiation technique combined with a low-fluorine solution process was developed to prepare YBCO films. An acrylic acidic group as the chelating agent was used in the precursor solution. The acrylic acidic group was highly sensitive to DUV light at 254 nm and significantly absorbed UV light. The coated gel films exposed to DUV light decomposed at 150 °C and copper aggregation was prevented. The UV irradiation promoted the removal of the carbon residue and other by-products in the films, increased the density and enhanced the crystallinity and superconductivity of the YBCO films. Using a solution with F/Ba = 2, YBCO films with thicknesses of 260 nm and enhanced critical current densities of nearly 8 MA/cm2 were produced on the LaAlO3 (LAO) substrates.

Highlights

Controlling the pyrolysis process was essential to ensure the quality of the YBCO films
We hypothesized that if UV irradiation was used to prepare the YBCO films, the Cu aggregation could be prevented and the films would be denser since the photo-activation process occurred at a low temperature, and YBCO films could be produced with enhanced Jc
We found that the full width of the half maximum (FWHM) for both the phi scanning and the omega scanning decreased with UV irradiation times, indicating that the in-plane and out-of-plane textures of the YBCO films improved

Summary

Introduction

Controlling the pyrolysis process was essential to ensure the quality of the YBCO films. The copper aggregated on the film surface after the Cu-salts decomposed during the pyrolysis process, which induced second phases inside the final annealed YBCO films. A solution process combined with deep ultraviolet (DUV) irradiation was reported, and high-performance oxide films were produced by Kim et al.[7]. Their work confirmed that the UV-irradiated film was denser than films prepared without UV irradiation From these results, we hypothesized that if UV irradiation was used to prepare the YBCO films, the Cu aggregation could be prevented and the films would be denser since the photo-activation process occurred at a low temperature, and YBCO films could be produced with enhanced Jc. In this study, we prepared YBCO films using a novel precursor solution sensitive to 254 nm of UV light. We studied the photochemistry during UV irradiation, the formation of the intermediate phases and the influence of UV irradiation on the chemical and physical properties of the films

Methods

Results

Conclusion