FLUX-CREEP ASSOCIATED WITH BULK PINNING AND EDGE BARRIERS IN BSCCO-2212 SINGLE-CRYSTALS

We have examined the flux creep behaviour in high-quality BSCCO-2212 s ingle crystals by dynamic relaxation of the global magnetization using a vibrating-sample magnetometer. The irreversible magnetization is at tributed to bulk pinning at low temperatures and to edge barriers at h igh temperatures. The increase of current at the anomalous 'arrowhead' feature is related to the penetration of a Bean-type profile through the sample at a field H. We show that at H* flux creep is enhanced. T he fast-creep regime survives over a narrow field range up to a field H-b, associated with the irreversibility line of the bulk pinning. Apa rt from the temperatures and fields where the arrowhead is observed, t he creep rate has a similar normalized field dependence at all tempera tures.