Reduced filament coupling in Bi(2223)/BaZrO3/Ag composite tapes

Multifilamentary Bi(2223)/Ag tapes often exhibit AC loss levels comparable to those measured in monofilamentary samples, which is partly due to the la rge coupling currents induced in the low resistive sheath material. Surroun ding the individual filaments by electrically insulating barrier layers sup presses these currents and strongly reduces the coupling. We demonstrate th is effect with various types of magnetic and self-field AC loss measurement s on a series of Bi(3223)/BaZrO3/Ag tapes. We also discuss the influence of barrier thickness, twist pitch length and filament arrangement on the meas ured losses in these composite conductors. (C) 1998 Published by Elsevier S cience B.V. All rights reserved.