Assessment of Chemical Solution Synthesis and Properties of Gd₂Zr₂O₇ Thin Films as Buffer Layers for Second-Generation High-Temperature Superconductor Wires

Abstract

Chemical solution processing of Gd 2 Zr 2 O 7 (GZO) thin films via sol-gel and metalorganic decomposition (MOD) precursor routes have been studied on textured Ni-based tape substrates. Even though films processed by both techniques showed similar property characteristics, the MOD-derived samples developed a high degree of texture alignment at significantly lower temperatures. Both precursor chemistries resulted in exceptionally dense, pore-free, and smooth microstructures, reflected in the cross-sectional and plan-view high-resolution scanning and transmission electron microscopy studies. On the MOD GZO buffered Ni-3at.% W (Ni-W) substrates with additional CeO 2 /YSZ sputtered over layers, a 0.8-m-thick YBa 2 Cu 3 O 7−␦ (YBCO) film, grown by an ex situ metalorganic trifluoroacetate precursor method, yielded critical current, I c (77 K, self-field), of 100 A/cm width. Furthermore, using pulsed-laser deposited YBCO films, a zero-field superconducting critical current density, J c (77 K), of 1 × 10 6 A/cm 2 was demonstrated on an all-solution, simplified CeO 2 (MOD)/GZO(MOD)/Ni-W architecture. The present study establishes GZO buffers as a candidate material for low-cost, all-solution coated conductor fabrication.

Transmission electron microscope study on electrodeposited Gd2O3 and Gd2Zr2O7 buffer layers for YBa2Cu3O7−δ superconductors

“…Similar voids have been reported previously in La 2 Zr 2 O 7 buffer layers grown by chemical solution deposition [10]. However, no voids were reported in chemically solution processed GZO films deposited using sol-gel and metal-organic decomposition precursor routes [11]. Voids are important because they can act as accelerated pathways for metal or oxygen diffusion, therefore degrading the superconductor properties.…”

Study on advanced Ce0.9La0.1O2/Gd2Zr2O7 buffer layers architecture towards all chemical solution processed coated conductors

“…16 Although the precursors, lms thicknesses and annealing procedures are the key factors in determining the texture quality of the CSD-buffer layer, there are seemingly no signicant microstructural differences among rare-earth zirconate layers, especially for the thick lms prepared by mono-coating routes. Additionally, the microstructure of the barrier plays an essential role in preventing the diffusion of metal elements from the substrate.…”

Electrodeposited Gd2Zr2O7 and Gd2O3 Buffer Layers for YBa2Cu3O7-δ Superconductors

“…[5][6][7][8] The successful growth of epitaxial Gd 2 Zr 2 O 7 (GZO) and Gd 2 O 3 (GO) by solution techniques has also been reported. 9,10 In this paper, we report on high-quality biaxially textured buffer layers with improved full-width at half maximum values of the omega and phi scans compared with the base Ni-W substrate, prepared inexpensively by an electrodeposition method. YBCO tapes prepared using this type of buffer layer produced pulsed-laser deposited (PLD) YBCOcoated conductor with J c of 3.3 · 10 6 A/cm 2 at 77 K in zero field.…”