Reduction of alternating magnetic field losses in high-Tc multifilament Bi(2223)/Ag tapes by high resistive barriers

Flat High-T-c multifilament tapes with an Ag matrix have very large coupling current losses in perpendicularly applied 50 Hz magnetic fields. By the application of ceramic isolating BaZrO3- and SrZrO3 barriers around the filaments we could reduce at 77 K the coupling current decay time constant to 1.5 ms, leading to a significant loss reduction at 25 Hz and a noticeable loss reduction at 50 Hz. The coupling loss maximum for small Delta B values was shifted for a stack of six tapes to 110 Hz and for a single tape to 180 Hz. By a further combined application of several loss reduction measures the application of High-T-c superconductors in 50 Hz magnets will be possible in the next future. (C) 1999 Elsevier Science Ltd. All Fights reserved.