Stitching of fluxoids parallel to the superconducting sheet in Bi2Sr2CaCu2O8+delta

In the two-dimensional superconductor Bi2Sr2CaCu7O8+delta, the fluxoids par allel to the superconducting plane can move freely along the plane, but whe n on an incline in relation to the plane their movement is impeded by pinne d pancake vortices. This behavior was studied in detail in the present stud y based on rf susceptibility measurements. The relaxation time for depinnin g was evaluated as a function of temperature and field by swinging crystals in a magnetic field in the proximity of the plane. The contribution of vor tex-antivortex annihilation to the liberation of fluxoids is also discussed . (C) 2001 Elsevier Science B.V. All rights reserved.