Alternating-current losses in silver-sheathed (Bi,Pb)2Sr2Ca2Cu3O10 tapes II: Role of interfilamentary coupling

Abstract

ac losses at 60 Hz have been measured for silver-sheathed (Bi,Pb)2Sr2Ca2Cu3O10 multifilamentary tapes at 27 and 77 K to investigate the role of interfilamentary coupling. The results are qualitatively well described by the use of the concept of the critical coupling length lc. Further, it is shown that to obtain effective reduction of the coupling loss, a very small twist pitch length (≪1 cm) as well as a substantial reduction in the filament thickness are required for an applied ac field of, for example, 100 rms A/cm at 77 K.