Reduction of AC Losses in Bi-2223 Tapes by Introducing Interfilamentary Oxide Barriers

AC loss reduction in Bi-2223 tapes is one of the key issues for the realization of power cables and transformers. The large loss generation is mainly attributed to the strong electromagnetic coupling between the filaments in AC external magnetic field. In this paper, we fabricated twisted Bi-2223 tapes with interfilamentary oxide barrier and evaluate their AC loss properties. To suppress the side effect on Bi-2223 phase formation during sintering, Ca₂CuO₃ or SrZrO₃ powders were used as barrier materials. Furthermore, small amounts of Bi-2212 powders were mixed with them to improve their ductility for cold working. AC loss characteristics were examined at 77 K in parallel and perpendicular transverse magnetic fields with various field amplitudes and frequencies. The effect of introducing different oxide barriers on AC loss reduction at different operating condition is discussed.