Superconducting properties of commercial REBCO-coated conductors with artificial pinning centers
K. Tsuchiya, Xudong Wang, S. Fujita, Ataru Ichinose, Kyohei Yamada, A. Terashima, A. Kikuchi
Abstract
Abstract Over the last 20 years, technologies for manufacturing rare-earth barium copper oxide (REBCO)-coated conductors have undergone a steady development. Currently, the properties of these conductors are reasonably stable owing to the intensive efforts of the manufacturers. However, for high-field magnet applications, such as the magnets used in nuclear magnetic resonance instruments, accelerators, and fusion reactors, further enhancements in the current-carrying capabilities and/or the current densities of the conductors under a high magnetic field are necessary. Recently, several conductors doped with artificial pinning centers (APCs) have become commercially available, primarily from four manufacturers: Fujikura, Shanghai ST, SuperOx, and SuperPower. In this study, we characterized these relatively new conductors from the viewpoint of a magnet designer. We measured the critical currents ( I c ) of full-size 4 mm wide conductors in a wide field range at 4.2 K and 77 K; we also measured the critical temperatures. The measurement results showed that the I c values at 4.2 K under perpendicular fields for these conductors are significantly greater than those of non-APC conductors; for the 4 mm wide conductors, the I c values are in the range of 300–740 A and 450–1000 A at 18 T and 12 T, respectively. Furthermore, we clarified that the non-Cu current density ( J c ) at 4.2 K for some of the investigated conductors is more than twice the J c of the recent Nb 3 Sn conductors in fields exceeding 15 T. In the investigated commercial REBCO-APC conductors, the highest layer J c of ∼60 kA mm −2 (at 18 T and 4.2 K) was noted. We also investigated the I c – B relationship at 4.2 K for the recent REBCO-APC conductors.