Magneto-optical imaging of flux patterns in multifilamentary (BiPb)2Sr2Ca2Cu3O<i>x</i> composite conductors

Abstract

We present a study of the superconducting morphology of the transport current carrying cross section of a 19-filament (BiPb)2Ca2Cu3Ox (Bi-2223) composite conductor using magneto-optical imaging of magnetic flux patterns. In conjunction with electron microscopy on the same sample this technique allows a unique correlation of superconducting and microstructural properties. Direct evidence for enhanced superconducting properties in platelike regions along the silver/Bi-2223 interface and for weak properties near the core of the filaments is obtained. Misaligned grain colonies are found to cause an interruption of the superconducting continuity in the filaments.