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Description
REBa₂Cu₃Oy (REBCO, where RE is a rare-earth element) coated conductors (CCs) fabricated using the trifluoroacetate metal organic deposition (TFA–MOD) method are among the most promising candidates for superconducting applications due to their low cost and excellent performance. High critical current (Ic) under magnetic fields is crucial for applications such as generators, nuclear magnetic resonance, magnetic resonance imaging, and nuclear fusion reactors. In a previous study, we successfully fabricated BaZrO3 (BZO) nanoparticle-doped Y0.77Gd0.23Ba2Cu3Oy (YGdBCO+BZO) CCs using a newly developed reel-to-reel system furnace [M. Sato et al., IEEE Trans. Appl. Supercond., 34, (2024) 3]. These 100-m-class YGdBCO+BZO CCs exhibited a highly uniform Ic distribution in the self-field at 77 K, with a minimum Ic of 102 A/cm-width at 70 K and 2.5 T. However, TFA-MOD YGdBCO+BZO CCs often contain significant amounts of second phases, such as CuO, Y2O3, and Y₂Cu₂O₅, which are detrimental to achieving high Ic. Thus, controlling the Ba/RE ratio in the starting solution is a key factor in reducing second-phase formation and improving in-field Ic.
In this study, we fabricated YGdBCO+BZO CCs with various Ba/RE ratios in the starting solution to suppress the second phase and enhance in-field Ic properties. The CCs with a Ba/RE ratio of 1.8 achieved a self-field Ic of 471 A/cm-width at 77 K, which is 1.25 times higher than that of CCs with a standard Ba/RE ratio of 1.5. This is attributable to the significant reduction in the second phases.
This paper focuses on the in-field Ic properties of YGdBCO+BZO CCs, including their performance at low temperatures and under high magnetic fields, offering insights into further optimizing their superconducting properties for advanced applications.
This study is based on findings obtained from Project, which was subsidized by the New Energy and Industrial Technology Development Organization.
