Superconducting joining of YBCO coated conductors without a large critical current loss

Achieving superconducting joinings with large current capacities is a challenge for magnetic resonance imaging applications of YBa2Cu3O7-delta (YBCO) coated conductors (CCs). Here we report a novel method to fabricate a superconducting joining between two YBCO CCs using a joining strap consisting of YBCO, Ag, a buffer, and a substrate. The YBCO layer exfoliated from the buffer stack of a YBCO CC can retain more than 90% of its original critical current (I-c). This is particularly due to the Ag layer serving as a fast oxygen diffusion path to promote the recovery of superconductivity of the YBCO layer during oxygenation annealing. The atomic arrangement at the joined YBCO interface is well aligned along the (001) plane, enabling superior superconducting performance. The method reported here provides a practicable solution to achieve persistent current mode operation in second-generation high-temperature superconducting magnet applications. (C) 2021 Published by Elsevier Ltd.