Two-dimensional fluctuations in the magnetization of Bi2Sr2Ca2Cu3O10.

Abstract

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 \ensuremath{\chi}(T) above ${\mathit{T}}_{\mathit{c}}$ can be fitted well in terms of the 2D Lawrence-Doniach model. Values of ${\ensuremath{\xi}}_{\mathit{a}\mathit{b}}$(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 ${\mathit{T}}_{\mathit{c}}$.