Field and Temperature Dependence of Susceptibility of Single Crystal Bi₂Sr₂CaCu₂O₈

Susceptibility measurements on Bi₂Sr₂CaCu₂O₈ single crystals do reveal field-induced-suppression of sharp phase transition. No apparent anisotropy of the susceptibility was observed when magnetic field was applied along the three main directions a, b and c. The three dimensional isotropic fluctuation diamagnetism theory is proposed to explain our experimental finding of isotropic susceptibility. In a wide range of magnetic field, the temperature dependence of susceptibility does not show any obvious change in its character when the sample enters into expected vortex-lattice state from vortex-liquid state.