THE EFFECT OF ANISOTROPY ON THE PHASE-DIAGRAM OF BI2SR2CACU2O8

We have studied the first-order vortex-lattice transition and the seco nd anomalous peak effect in BSCCO single crystals with several anisotr opies using the local Hall-probe technique. We find that the first-ord er phase transition line shifts upward for more isotopic over-doped cr ystals. The first-order line ends at a critical point and another shar p transition line associated with the second magnetization peak contin ues to lower temperatures. Both lines form a continuous phase transiti on line which is anisotropy dependent.