Texture development studies in Ag-sheathed Bi-2223 tapes

Abstract

A novel magnetic procedure has been introduced for the determination of the degree of texturing of the superconducting grains in Ag-sheathed (Bi, Pb)2Sr2Ca2Cu3Ox tapes. Our new method is based on the observation that, in the BSCCO family of superconductors, a relevant anisotropy is present between the in-plane and out-of-plane critical current densities of individual crystallites. By neglecting the magnetic moment of the single grain due to out-of-plane circulating currents, and by comparing magnetic hysteresis loops measured within different field orientations with respect to the tape direction, it has been possible to determine the average degree of texture of an assembly of BSCCO superconducting grains. As a result of our simple approach, we have measured the texture evolution of the precursor grains during the cold deformation process of unreacted multifilamentary (Bi, Pb)2Sr2Ca2Cu3Ox tapes; moreover, we have been also able to distinguish between longitudinal and transverse texture of the grains with respect to the tape direction. Finally, the usefulness of our method has been verified on tapes prepared with various precursor powders and cold deformation techniques.