Critical current measurement of commercial REBCO conductors at 4.2 K

TLDR

REBCO coated conductors are commercially available and are being pursued for high‑field magnets, yet limited data exist on their transport properties at low temperature and high field, a gap critical for magnet design and projects such as CERN’s Future Circular Collider. This work develops a new sample holder to facilitate measurement of full‑width REBCO conductors and investigates the transport properties of conductors from seven manufacturers at 4.2 K up to 18 T. Using the new holder, the authors measured critical current in perpendicular magnetic fields up to 18 T on 4‑mm‑wide conductors from AMSC, Fujikura, Shanghai Superconductor, SuNAM, SuperOx, SuperPower, and SWCC Showa. The measurements reveal that Ic values vary among the conductors, with the highest‑current samples achieving 230–305 A at 18 T and 320–424 A at 12 T.

Abstract

REBCO coated conductors are now available from several industrial manufacturers and are expected to be promising conductors for high-field-magnet applications. Using these conductors, the development of solenoids capable of generating high magnetic fields of 20–30 T is ongoing in major high-field laboratories in the world. In addition, CERN recently launched a conceptual design study for the Future Circular Collider, in which a 20-T dipole magnet is listed as a candidate for the bending magnet of the main ring. However, there has been limited research published on the electrical transport properties of commercially available REBCO conductors in a high-field, low-temperature environment. For magnet designers, the transport properties are of the highest importance in choosing a suitable conductor, and the data form the bases for high-field magnet development. Therefore, in this work, a new sample holder, which allows the measurements of full-width conductors to be carried out relatively easily, was developed, and the transport properties of commercial REBCO conductors from seven manufacturers (AMSC, Fujikura, Shanghai Superconductor, SuNAM, SuperOx, SuperPower, and SWCC Showa) were investigated at 4.2 K in perpendicular fields of up to 18 T. The results show that the Ic values at 4.2 K clearly vary to some extent among these commercial conductors and the higher-current 4-mm-wide conductors have Ic values in the range of 230–305 A at 18 T and in the range of 320–424 A at 12 T.