Iodine Intercalation into the Bi2212 Superconductor Using FeI₂ as a Reactant

Abstract

We examined the possibility of FeI₂ intercalation into Bi₂Sr₂CaCu₂O_y polycrystalline superconductor. It was found that FeI₂ was not intercalated in Bi₂Sr₂CaCu₂O_y, but I_xBi₂Sr₂CaCu₂O_y and Fe₂O₃ were produced by vapor phase reaction of Bi₂Sr₂CaCu₂O_y and FeI₂. Separation of diffraction lines (200), (020) for I_xBi₂Sr₂CaCu₂O_y suggest that the oxygen of Bi₂Sr₂CaCu₂O_y reacted with Fe of FeI₂. Lattice constance c for I_xBi₂Sr₂CaCu₂O_y varied from 18.3 to 18.8 with increasing x. I_xBi₂Sr₂CaCu₂O_y coexisted with Bi₂Sr₂CaCu₂O_y between x=0.67 and 0.90. Resistance was increased and Tc was lowered by iodine intercalation.