Ultra-fast growth of cuprate superconducting films: Dual-phase liquid assisted epitaxy and strong flux pinning

Cuprate superconductors are key candidate materials toward high energy-efficient devices. Improving their growth rate and performance under magnetic fields are indispensable for achieving even higher efficiency. For the first time, we demonstrated the ultra-high rate up to 100 nm/s in the growth of dualphase cuprate superconducting film (EuBa2Cu3O7-BaHfO3). The growth rate achieved is two orders of magnitude higher than that at lab-scale and was also the highest on record to our best knowledge. Epitaxial growth mechanism assisted by the transient liquid phase is proposed, as evidenced by formation of Eu2BaCuO5 and Ba-Cu-O metastable phases under high supersaturation conditions. The high growth rate results in formation of mixed defective landscape, consisting of short nanorods, nanoparticles and naturally formed defects (e.g., staking faults). Due to such unique microstructure, we confirm that weak J(c) anisotropy is dominated by random pinning mechanism. Contribution of isotropic and anisotropic J(c) to J(c)(total) also varies with temperatures and magnetic field strength, which is a consequence of evolution of dominant pinning in film. As a result, the in-field current carrying capacity is significantly enhanced (exceeding 430 A/4 mm-width at 4.2 K, 18 T, B//c), being among the top tier of commercialized superconductor materials. This study establishes the correlation between ultra-high growth rate and flux pinning behaviors, which provides feasibility of dramatically improvement of production efficiency with the low price-performance ratio of future high temperature superconductor. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study demonstrates the ultra-high growth rate of dual-phase cuprate superconducting film and its impact on performance and behavior under magnetic fields. By investigating the epitaxial growth mechanism and defect structure, the dominant mechanism of weak J(c) anisotropy is confirmed. The research provides important insights for significantly improving production efficiency of future high temperature superconductors.