Anomalous magnetization characteristics in the overdoped Bi2-xPbxSr2CaCu2O8+delta single crystal

Magnetization measurements with the magnetic field parallel to the c-axis w ere performed on overdoped Bi2-xPbxSr2CaCu2O8+delta single crystals. Differ ent from undoped Bi2Sr2CaCu2O8+delta single crystal, a pronounced anomalous peak with maximum peak field over 5000 G can be observed in enlarging temp erature window from 0.2T(c) to 0.9T(c); both the anomalous magnetization pe ak H-2p and the sharp onset of the anomalous magnetization peak H-on exhibi t strong temperature dependence up to the vicinity of T-c. The temperature dependence of H-on and H-2p implies that observed anomalous magnetization o riginates from a static disorder-induced transition from a relatively order ed vortex lattice (or Bragg glass) to a vortex glass (or disordered vortex solid) at H-on and thermal disorder induced pancake vortex decoupling trans ition at H-2p.