Friday, 2E-03, -

Rapid Fabrication of IBAD-MgO and LaMnO₃ Layers for REBCO Coated Conductor

Hiroyuki Fukushima

Masateru Yoshizumi¹, Seiki Miyata¹, Reiji Kuriki¹, Akira Ibi¹, Yutaka Yamada¹, Teruo Izumi¹, Yuh Shiohara¹, Takeharu Kato² and Tsukasa Hirayama²

¹ISTEC-SRL; Shinonome 1-10-13, Koto-ku, Tokyo, Japan, 135-0062
²Japan Fine Ceramic Center; Mutsuno 2-4-1, Atsuta-ku, Nagoya, Japan, 456-8587

Highly texture development of CeO2 by PLD method was found in Ion-Beam-Assisted Deposition(IBAD)-MgO substrate. The in-plane alignment was improved from 15 degrees in MgO layer to 3.7 degrees in CeO₂. Insertion of thin LaMnO3 (LMO) layer between IBAD-MgO and CeO₂ layers was indispensable to this phenomena (we call Self-Epitaxy of CeO₂ ). The LMO layer is deposited by RF sputtering. It's considered to relax the large misfit between lattice constants of MgO and CeO₂. Without LMO layer, the in-plane alignment of CeO₂ layers was hardly improved. LMO deposition realized a production rate of 30 m/h in the small deposition area (6x13cm₂). The Using the self-epitaxy, we developed new architecture of buffer layers of textured substrate, CeO₂/LMO/IBAD-MgO/Gd-Zr-O/Hastelloy. Using new substrate with the self-epitaxy, GdBa₂Cu₃O_7-α(GdBCO) layer was deposited by PLD method and high critical current of 500 to 600 A at 77K and self-field was obtained for short samples. We also developed reel-to-reel deposition system with DC reactive sputtering for MgO deposition for long textured substrate fabrication. This system achieved high production rate of 150 m/h and high I_c over 200 A at 77 K in self-field. The high texturing degree and high production rate in this system were very promising for low-cost coated conductor processing. Recently, the production rate of LMO layer was further increased to 50 m/h using the above-mentioned small deposition area. We report the details of rapid fabrication of IBAD-MgO and LMO layers.

This work was supported by New Energy and Industrial Technology Development Organization (NEDO) as the Project for Development of Materials & Power Application of Coated Conductors, M-PACC.

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