CRITICAL FLUCTUATIONS IN THE MAGNETIZATION OF BI2SR2CACU2O8 NEAR THE H(C2)(T) LINE

The magnetization measurements on Bi2Sr2CaCu2O8 single crystals with H parallel to the c axis are presented to show that the critical fluctu ations in the magnetization near the H(c2)(T) line can be well studied within the two-dimensional nonperturbative scaling theory developed b y Tesanovic et al. By using this scaling theory and basic thermodynami c arguments, we obtained the Ginzburg-Landau parameter kappa (congruen t-to 115) and dH(c2)/dT (congruent-to -2.7 T/K) near T(c) for this mat erial. In addition, we found that these derived parameters are in good agreement with those determined from the study of reversible magnetiz ation in an intermediate field at low temperature.