Two-dimensional fluctuations in the magnetization of Bi2Sr2Ca2Cu3O10

Magnetization measurements on c-axis-oriented bulk Bi2Sr2Ca2Cu3O10 with the magnetic field parallel to the c axis are reported. The results show large fluctuation effects, which can be explained by Ginzburg-Landau fluctuation theory for a two-dimensional (2D) system. The magnetization in high fields displays good scaling behavior as a function of [T-Tc(H)]/(TH)1/2. The weak-field fluctuation diamagnetic susceptibility χ(T) above Tc can be fitted well in terms of the 2D Lawrence-Doniach model. Values of ξab(0) and dHc2/dT derived from our fluctuation analysis are consistent with those obtained by fitting the Hao-Clem variational model to the reversible magnetization data below Tc.