We have investigated the influence on the superconductivity of the iodine intercalation into sintered samples of Bi2212 and Bi2223 superconductors by using I₂ or FeI₂ as reactant. It has been found from X-ray diffraction that iodine intercalated compound of IXBi₂Sr₂Ca₂Cu₃Oy was prepared by intercalation by using FeI2. The iodine intercalation using FeI₂ as a reactant into Bi2223 phase is reported for the first time as long as we know.
The decrease of T_Conset, ΔT_Con, for Bi2223 was smaller than one for Bi2212. This is likely due to the number of the CuO₂ planes between BiO planes. In the case using FeI₂, I₂ originates from FeI₂ with reduction of host.