21-25 July 2019
Connecticut Convention Center, Level 6
US/Eastern timezone

M1Or1A-02 [Invited]: Development of BMO Doped REBCO Coated Conductors with Homogenous In-field Properties by Productive Hot-Wall PLD Process

22 Jul 2019, 10:00
30m
Level 6, Room 14 ()

Level 6, Room 14

Speaker

Dr Yasuhiro Iijima (Fujikura Ltd.)

Description

In order to overcome the narrower deposition windows and less longitudinal homogeneity for high in-field performance BaMO3 (M : Zr or Hf etc.) doped REBCO film, we applied hot-wall type pulsed-laser-deposition (PLD), which realized quite homogeneous crystalline growth conditions for REBCO by furnace-like substrate heating without spoiling productive throughput.
We studied growth condition dependence of BMO nano-rod structure, and Jc (B, theta, T) properties. Clear growth rate dependence were observed for c-axis correlated flux pinning properties and the shape and densities of nano-rod structure which should be affected by adatom migration durations. Though the minimum Jc (theta) of those samples were not so different at the temperature over ~30 K, the difference increased gradually at lower temperatures. The minimum Jc (theta) increased up to four times bigger for low growth rate samples of 5-7 nm/sec, as two-times for high-growth rate samples of 20-50 nm/sec, than non-doped REBCO films, at 4.2 K, 15 T.
The temperature and field dependent scaling properties were also studied for pinning force densities at the field configuration parallel to c-axis. The results indicated that strong c-axis correlated pinning could be only observed in low growth rate samples, where high-growth rate samples of >20 nm/sec had quite simple scaling properties similar to non-doped samples.
We finally optimized the deposition parameters so that they contribute to both good productivity with high growth rate of 20-50 nm/sec, and less angular dependent and large enough in-field Ic properties which agree to Jc-B scaling law in wide temperature and field range. Production samples of 300-600 m long were routinely fabricated and test samples of 1 km long class also produced with good Ic uniformity comparable to non-doped REBCO wires. Ic uniformity was examined by scanning Hall probe microscopy (RTR-SHPM), and also end-to-end transport measurement in magnetic fields, etc. A part of this work is based on results obtained from a project subsidized by the New Energy and Industrial Technology Development Organization (NEDO).

Primary authors

Dr Yasuhiro Iijima (Fujikura Ltd.) Dr Kazuomi Kakimoto (Fujikura Ltd.) Mr Shinji Fujita (Fujikura Ltd.) Mr Shogo Muto (Fujikura Ltd.) Mr Tomo Yoshida (Fujikura Ltd.) Wataru Hirata (Fujikura Ltd.) Mr Yutaka Adachi (Fujikura Ltd.) Ryo Kikutake (Fujikura Ltd.) Mr Masanori Daibo (Fujikuar Ltd.) Prof. Satoshi Awaji (Institute for Materials Research, Tohoku University) Takanobu Kiss (Kyushu University)

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