Two different kinds of stage-1 iodine intercalates of Bi2Sr2CaCu2Oywith dissimilarTchave been prepared in order to understand the relationship between superconducting properties and electronic structures. According to the XRD analysis and the magnetic susceptibility measurements, it is found that, in spite of the same basal increments for both intercalates (Δd=~3.6 Å), the iodine intercalate prepared in a vacuum-sealed tube exhibits a largerTcdepression (13 K) compared to the iodine intercalate synthesized in air (ΔTc=6 K). The origin of such differentTcshifts has been investigated by performing the systematic XANES/EXAFS analyses at the I L1-, Cu K-, and Bi L3-edges, where the charge transfer between host and guest is found to be strongly dependent on the reaction condition. From the BVS calculation based on the Cu K-edge EXAFS results, it is clarified that there is an excellent correlation between the amount of hole doping andTcdepression for both iodine intercalates. In this respect, we conclude that, regardless of lattice expansion along thec-axis, theTcof Bi-based cuprate is wholly dependent on the hole concentration of the CuO2layer.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry