Iodine intercalation effect on the critical fluctuation of Bi2Sr2CaCu2O8 single crystal

The magnetization of iodine intercalated Bi2Sr2CaCu2O8 (I + Bi-2212) single crystal has been measured as a function of magnetic field H and temperatur e T. The extracted fluctuation part of the magnetization exhibits a critica l behavior consistent with the three dimensional XY model. The static criti cal exponent v is 0.99 +/- 0.1, which is increased from the Value 0.77 + 0. 1 for pristine Bi-2212, indicating that the weak interlayer coupling along the c-axis of iodine intercalated Bi-2212 significantly increases the stati c critical exponent v. This result supports that Bi-2212 has an increased s tatic critical exponent v that is larger than the value of 0.669 of YBa2Cu3 O7-delta (YBCO) single crystal.