Enhanced Electrical and Mechanical Performances of Soldered Joint Between Copper Stabilized REBCO Superconducting Tapes

Low-resistance joint development for segment-fabrication of high-temperature superconducting fusion magnets

“…On the other hand, it has been reported that the interface resistivity (interface resistance, R REBCO/Ag or R REBCO/Ag +R Ag/Cu , for the unit area) inside the REBCO tape strongly depends on manufacturers and batch (lot) number as well as the positioning of the the REBCO tape. There are many reports which measured the interface resistivity, using a three-probe method [51,52], a four-probe method [53,54] and a current transfer length (CTL) method [55][56][57]. The evaluated interface resistivity also varies depending on the evaluation method; 0.05-0.07 pΩm 2 for silver-stabilized REBCO tapes having only R REBCO/Ag by a three-probe method [51,52], 0.6-1.2 pΩm 2 for copper-stabilized REBCO tapes having R REBCO/Ag +R Ag/Cu by a four-probe method [53,54], and [55][56][57].…”

“…There are many reports which measured the interface resistivity, using a three-probe method [51,52], a four-probe method [53,54] and a current transfer length (CTL) method [55][56][57]. The evaluated interface resistivity also varies depending on the evaluation method; 0.05-0.07 pΩm 2 for silver-stabilized REBCO tapes having only R REBCO/Ag by a three-probe method [51,52], 0.6-1.2 pΩm 2 for copper-stabilized REBCO tapes having R REBCO/Ag +R Ag/Cu by a four-probe method [53,54], and [55][56][57]. To note the reason as to why the interface resistivity obtained by the threeprobe method was so low cannot be ascertained at this time.…”

Static magnetic field amplification in high-T c superconducting flux transformer equipped with multi-turn coil prepared using REBCO tape conductor

“…[6][7][8][9] Therefore, SFTs equipped with multi-turn coils can be easily fabricated. On the other hand, the joining techniques currently adopted for HTS wire [10][11][12] are not practical due to restrictions in terms of processing time, the shape of the joints and the superconductivity of the joints. For such reasons, HTSFT can be prepared by patterning HTS thin films on single-crystal substrates or tape conductors to create the essential superconducting closed circuits.…”

Preparation of a high-T c superconducting magnetic flux transformer with a 100 mm bore coil and static magnetic field transfer at 77 K.

“…6,7) Several jointing methods have been proposed for cuprate HTSs. However, all these methods have significant challenges that need to be addressed: (1) solder materials such as lead and bismuth show superconductivity approximately at the liquid helium temperature; therefore, the soldering joint at the liquid nitrogen temperature functions only as a low-resistance joint, [8][9][10] which certainly differs from a superconducting joint connecting the quantum phase of both sides. (2) Joints using deposition of superconductor and insulator layers enable multi-turn coil; 11,12) however, high vacuum equipment is required for their preparation and the sample size is limited to the size of the vacuum apparatus.…”