In-Field Electrical Resistance at 4.2 K of REBCO Splices

Low resistance electrical splices between rare-earth barium copper oxide (REBCO) coated conductors are key technology for high temperature superconductor magnets. A splice must satisfy two main requirements: 1) reproducible low electrical resistance; and 2) high mechanical strength. Systematic measurements of the splices are required because the internal interface resistances of the REBCO-coated conductor (e.g., REBCO/Ag interface) are difficult to be predicted. In this paper, the electrical resistance of lap joints made from REBCO tapes produced by different manufacturers has been experimentally investigated at 4.2 K and in fields of up to 12.4 T. The same sample splices were also measured at 77 K and in self-field in order to define a lift factor correlating joints resistances at 77 and 4.2 K. As expected, a strong effect on the conductor orientation in the splice was found.