Transport measurements have been made on ${\mathrm{Bi}}_2{\mathrm{Sr}}_2{\mathrm{CaCu}}_2{\mathrm{O}}_8$ single crystals in the Corbino disk geometry where vortices should not cross the sample edges in a fixed applied field. The results are compared directly with a strip geometry by cutting the disk into a strip and remeasuring the sample using the same contacts. Pronounced differences are observed in both the resistive transition and the current-voltage characteristics in these two geometries. The critical current density in the vortex solid phase is at least 20 times smaller than usual estimates for a strip geometry. We conclude that the transport properties of ${\mathrm{Bi}}_2{\mathrm{Sr}}_2{\mathrm{CaCu}}_2{\mathrm{O}}_8$ samples in the strip geometry are dominated by surface barriers in both solid and liquid vortex phases over a wide range of fields and temperatures.

• Received 17 November 1998

DOI:https://doi.org/10.1103/PhysRevB.60.R757