EVIDENCE FOR THE QUASI-2-DIMENSIONAL BEHAVIOR OF THE VORTEX STRUCTUREIN BI2SR2CACU2O8 SINGLE-CRYSTALS

AC susceptibility and dc magnetization measurements on Bi2Sr2CaCu2O8 ( BSCCO) single crystals in a wide range of temperatures clearly show th at below the dc irreversibility line the vortex system loss the long r ange order in the c direction. The susceptibility data taken at 7 Hz s how the different nature of two dissipation peaks: One related to the interplane currents at temperatures well below the dc irreversibility line and the other associated with the intraplane ones at temperatures above that line. In this sense the irreversibility line corresponds t o the temperature where quasi-two dimensional vortices are depinned.