Development of a superconducting joint between a GdBa₂Cu₃O_7-δ-coated conductor and YBa₂Cu₃O_7−δbulk: towards a superconducting joint between RE (Rare Earth) Ba₂Cu₃O_7−δ-coated conductors

Abstract

We have started to develop a superconducting bridge joint between two GdBa2Cu3O7−δ (Gd123)-coated conductors, where both conductors are placed in an end-to-end arrangement on the surface of a melt-textured YBCO (including Y2BaCuO5 and YBa2Cu3O7−δ) bulk, which acts as a superconducting medium between the coated conductors. As a first step in the development, one half of the bridge joint assembly was modeled and investigated. Experimental results achieved are as follows: (a) the higher-melting-temperature textured Gd123-coated conductor acts as a seed for the melt texture of the YBa2Cu3O7−δ (Y123) bulk, and (b) the superconducting phase continues across the Y123/Gd123 boundary. The critical current of the joint model is 10 A, which is about 10% of the original Gd123-coated conductor, at 77 K in a self-magnetic field. These results are considered to be extensible to the superconducting bridge joint between the Gd123-coated conductors.

High I c superconducting joint between Bi2223 tapes

“…A direct superconducting joint between RE123 tapes by atomic diffusion via partial melting state was demonstrated. 8) In addition, the epitaxial growth technique can be applied to connect the conductors using a RE123 melt-solidified bulk 9) or a short RE123 thin film. 10) For Bi2212 wires, the melt-solidification technique was found to be suitable for the preparation of superconducting joints with high I c , 11) because Bi2212 crystals are easily generated from the partial melting and slow-cooling process.…”

<b>Development of a Real-scale REBCO Coil for the Demonstration of a Magnetomotive Force of 700 kA</b>

“…If the coil is operated in persistent current mode, the current quickly decays. Establishment of the superconducting connection technique [6] and commercially available long-length coated conductors [7] are desired to allow persistent current mode operation. …”

<b>Experimental Production and Evaluation of Racetrack Coils for REBCO On-board Magnet</b>

“…It is considered that the persistent current mode of an on-board RE-BCO magnet is not available at present. Although reports on the superconducting joint between the REBCO conductors do exist [4], it has not yet reached a practical stage. Since the length of commercial REBCO conductors is only several hundred meters, coils require a high number of soldered joints.…”