Characterization of Multifilamentary REBCO Coated Conductor Coil Fabricated by Using the Process of Scratching the IBAD-MgO Layer

REBa₂Cu₃O_x (REBCO, RE = rare earth) coated conductors (CCs) are expected to show high performance for superconducting coil applications due to their high tensile strength and high critical current density under magnetic fields. One of the most serious problems on the coil application is the significant screening current, which is caused by the configuration of CC. Since screening current is dependent on the width of the REBCO layer, filamentization of the REBCO layer is strongly desired. We have succeeded in fabricating long length four-divided multifilamentary CCs with 4 mm wide over 100 m long by using the process of scratching the IBAD-MgO layer (scratching process). In this work, we fabricated two epoxy-impregnated coils and investigated the effects of the screening current. One of the coils is wound with multifilamentary CCs fabricated by scratching process, another is wound with conventional mono-filamentary CC. As the results, it is confirmed that the screening current is reduced and the coupling current between the filaments might be in the acceptable range on the DC magnet application.