Reduction of AC losses in Bi,Pb(2223) tapes by the introduction of barriers and the use of new wire configurations

Abstract

The level of AC losses is still too high in Bi,Pb(2223) tapes to allow their use in many applications. Therefore the reduction of AC losses in Bi,Pb(2223) is a key factor for their economical viability. The reduction of AC losses can be achieved by twisting of the tapes, alloying of the sheath or introducing a resistive barrier between the filaments. Up to now, the lowest value ever reported for a Bi,Pb(2223) tape in a parallel magnetic field of 0.1 T at 50 Hz is P=0.33 mW/Am, which is near the requirements for practical applications. On the other hand, when the applied field is perpendicular to the tape surface, the level of the AC losses is still too high and the critical current densities of such tapes is too low. We developed square wires, which allow the use of smaller twist pitches than in conventional tapes and have reduced anisotropy. We report on the effect of this new configuration on the level of AC losses.