Recently, we proposed two methods of joint, as crystalline joint by melted bulk (CJMB) for REBCO-coated conductors, and joint by incongruent melting (JIM) for Bi2223 tapes [1-3]. All the superconducting joints were obtained with critical current of about 10–60 A in 77 K and self-magnetic field. In this study, a hetero junction between RE123-coated conductor and Bi2223 tape was focused toward development of high field RE123/Bi2223 magnet for NMR and MRI. To operate under persistent current mode, some joints are necessary with low resistance, such as 0.1 nV. At last ISS2019, we reported the results of fabrication of the RE123–Bi2223 junction with measurements of XRD and I-V properties, and the results indicated that a reaction occurs at the RE123–Bi2223 boundary to affect the formation of superconducting junction. In this study, we prepared a junction with intermedium of Ag microlayer as RE123–Ag–Bi2223 structure, and a low resistance was obtained at 77 K. Further study to reduce the resistance will be carried out in this year. The fabrication methods and properties of the hetero junctions RE123–Bi2223 and RE123–Ag–Bi2223 will be presented in ISS2020.

Keywords: coated conductor, RE123, Bi2223, joint