HOMOGENEITY STUDY OF BI-2223/AG MONOFILAMENTARY TAPES USING HALL SENSOR MAGNETOMETRY

In this paper we report a homogeneity study of Bi-2223/Ag monofilamentary tapes prepared by two different mechanical deformation processes, rolling and semi-continuous pressing. We demonstrate how effects of mechanical deformation and heat treatments on the sample homogeneity and local critical current density can be revealed using Hall sensor magnetometry, Typical features of measured magnetic flux density profiles are interpreted by comparing the profiles to data obtained from resistive critical current measurements, SEM micrographs and numerical calculations based on simplified models of screening current distributions. Our experimental results are in agreement with the concepts that pressing leads to a rather homogeneous transport current path in a Bi-2223/Ag tape and rolling is likely to induce transversal cracks and necking in the superconducting ceramic.