Angular dependence of the fluctuation-induced magnetization of single-crystalline ${\mathrm{Bi}}_2$${\mathrm{Sr}}_2$${\mathrm{CaCu}}_2$${\mathrm{O}}_8$ near ${\mathit{T}}_{\mathit{c}}$

We report a detailed measurement of the magnetization for a high-quality ${\mathrm{Bi}}_2$ ${\mathrm{Sr}}_2$ ${\mathrm{CaCu}}_2$ ${\mathrm{O}}_8$ single crystal as a function of magnetic field (H) and the angle between H and the c-axis, near the transition temperature ${\mathit{T}}_{\mathit{c}}$. The fluctuation magnetization for H parallel to the c-axis was found to be in excellent agreement with the recently developed vortex-fluctuation theory by Bulaevskii et al. and the order-parameter fluctuation theory by Tešanović et al. However, our fluctuation magnetization data for the fields, applied at a large angle with respect to the c-axis, were found inconsistent with the expectations from the above theories.