A self-consistent study of vortex pinning/dynamics in single-crystal BSCCO-2212 platelet and prism specimen geometry

Predictions of a treatment, which includes specimen shape, vortex pinning and surface effects, are self-consistently fitted to experimental BSCCO-2212 magnetisation data for platelet and ‘prism’ single-crystal specimen geometries. The platelet specimen manifests, in accordance with theoretical expectation, a sharp dimensional cross-over transition from 3D to quasi-2D (arrowhead) behaviour at about the predicted cross-over field B 2D in the regime T≤40 K. The magnetic hysteresis in this specimen is shown to be predominantly due to the shape/geometry effect and, respectively, to 3D small-bundle and large-bundle collective pinning behaviour above and below this transition. The prism specimen shows a ‘diffuse’ cross-over transition, and the hysteresis is shown to be dominated by surface vortex pinning and a ‘distributed surface-barrier’ mechanism.