Superconducting properties of commercial REBCO-coated conductors with artificial pinning centers

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 Nb3Sn conductors in fields exceeding 15 T. In the investigated commercial REBCO-APC conductors, the highest layer J (c) of similar to 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.

Automated summary

The research investigates the development and commercialization of rare-earth barium copper oxide coated conductors, as well as the current-carrying capabilities of conductors doped with artificial pinning centers in high magnetic fields. The testing results show that conductors with artificial pinning centers have significantly higher critical current values under perpendicular fields and perform well under high magnetic fields.