Reduction in alternating-current transport losses of a (Bi, Pb)₂Sr₂Ca₂Cu₃O_x multifilamentary tape-form conductor by the introduction of resistive barriers

We succeeded in reducing alternating-current (ac) transport losses at 77 K and 50 Hz for the (Bi, Pb)₂Sr₂Ca₂Cu₃O_x tape-form conductor with 39 filaments, fabricated by a four-roller machine to make a rectangular deformation and also by the introduction of Bi₂Sr₂CuO_x sheets as resistive barriers in an arrangement parallel to a tape surface. Although the main contribution to the losses comes from the hysteresis loss of the superconductor, the loss value for the conductor is reduced by approximately 70% compared with the value for the (Bi, Pb)₂Sr₂Ca₂Cu₃O_x multifilamentary tape prepared by an ordinary powder-in-tube process without the resistive barriers. Using numerical calculations we ascribe this loss reduction to the division of field-free-core under ac current transmission, caused by introduction of the barriers.