Magnetic hysteresis loss in Bi-2223/Ag tapes with different filament arrangement

Abstract

Hysteresis losses in perpendicular AC magnetic field were investigated experimentally on a set of six Bi-2223/Ag tapes with different filament architecture. Along with a monocore tape and a tape with overlapping filaments, tapes with filament arranged in less or more regular stacks, as well as a tape with filaments perpendicular to the tape wide face were tested. AC susceptibility technique was used, allowing to present the loss behavior in terms of two multiplicative parameters: the external susceptibility at low amplitudes, χ 0, and the imaginary part of internal susceptibility, χ″. We show that both the filament stacking and its parallel orientation with respect to the applied field suppress χ 0, leading to hysteresis loss reduction. However, the unconventional filament architecture was accompanied by imperfections of filament microstructure that broadened the susceptibility peak. Then, the loss reduction in these tapes was less than expected. In the temperature interval 77–95 K, excellent scaling of the susceptibility data was found, indicating the validity of the critical state model for these systems.