Two-dimensional fluctuations in the magnetization of ${\mathrm{Bi}}_2$${\mathrm{Sr}}_2$${\mathrm{Ca}}_2$${\mathrm{Cu}}_3$${\mathrm{O}}_{10}$

Magnetization measurements on c-axis-oriented bulk ${\mathrm{Bi}}_2$ ${\mathrm{Sr}}_2$ ${\mathrm{Ca}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_{10}$ 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-${\mathit{T}}_{\mathit{c}}$(H)]/(TH${)}^{1/2}$. The weak-field fluctuation diamagnetic susceptibility χ(T) above ${\mathit{T}}_{\mathit{c}}$ can be fitted well in terms of the 2D Lawrence-Doniach model. Values of ${\xi }_{\mathit{a}\mathit{b}}$(0) and ${\mathit{dH}}_{\mathit{c}2}$/dT derived from our fluctuation analysis are consistent with those obtained by fitting the Hao-Clem variational model to the reversible magnetization data below ${\mathit{T}}_{\mathit{c}}$.