The Superconducting Properties of [001] Twist Boundaries in a Bi-Sr-Ca-Cu-O Superconductor

Critical temperature (Tc) and critical current density (Jc) of [001]-twist bicrystals of the Bi2Sr2CaCu2Ox were measured as a function of twist angle. The resistivity-temperature curve of the bicrystal showed a long tail, which was enhanced as the applied current increased. The Jc values of the bicrystals are 3-4 orders of magnitude lower than that of single crystals but relatively high Jc values were obtained for bicrystals at Σ5 and Σ17 coincidence orientation relationships. It was indicated that the [001] twist boundary in Bi2Sr2CaCu2Ox was the weak link, and is suggested that there existed a less detrimental grain orientation.