FLUX-PINNING CHARACTERISTICS IN BI-2212 SINGLE-CRYSTAL

Measurements were carried out on the critical current density and irreversibility line for a Bi-2212 single crystal prepared by the traveling solvent floating zone method. The observed critical current density was about two orders of magnitude smaller than that in a Bi-2212 specimen prepared by a melt process. This seems to be attributable to the small number density of effective pinning centers in the single crystal. The corresponding irreversibility field is also smaller than that of the melt-processed specimen. It is concluded from the result that the irreversibility field is largely influenced by the flux pinning strength.