MICROSTRUCTURE ANISOTROPY AND CRITICAL CURRENTS IN SILVER-SHEATHED BI2223 TAPES

The effective misalignment angle of the Bi2223 tape, phi(eff), can be derived by transport measurement in a magnetic field. By SEM observati on, this angle was found to be identical to the average crystallograph ic grain misalignment angle. Also, the angle is not influenced by fast neutron radiation. These facts prove that the crystallographic misali gnment of the grains determines the critical current anisotropy of the tape. A model is proposed that this typical value is mainly determine d by intrinsic mechanical properties of the Bi2223 compound and is a r esult of the mechanical deformation of the tape during the tape fabric ation.