A new high-T/sub c/ superconducting intercalation compound

Summary form only given. Intercalation of transition metal halides, M/subp n+/X/sub n/ (M=4d, 5d transition metals), into the layered superconducting oxides may lead to a new type of high-T/sub c/ superconductor. Among numerous transition metal halides, we found that silver iodide could be successfully intercalated into the Bi/sub 2/Sr/sub 2/CaCu/sub 2/Oy superconductor. A new high-T/sub c/ superconducting intercalation compound, Ag-1 Bi/sub 2/Sr/sub 2/CaCu/sub 2/Oy, has been prepared from the polycrystalline mixture of silver metal and Bi/sub 2/Sr/sub 2/CaCu/sub 2/Oy powders under P(I/sub 2/) /spl tilde/ 1 atm.. According to the X-ray diffraction analysis, the observed increase of 7.3/spl Aring/ in c-axis upon silver-iodine intercalation indicates that the lattice expansion for Ag-l- Bi/sub 2/Sr/sub 2/CaCu/sub 2/Oy is twice as large as that for the first-staged iodine intercalated Bi/sub 2/Sr/sub 2/CaCu/sub 2/Oy: Such a result suggests the gallery contains a double layer of iodine. A slight decrease in T/sub c/ for the Ag-I- Bi/sub 2/Sr/sub 2/CaCu/sub 2/Oy compared to the pristine has been observed by the de magnetic susceptibility measurements. A detailed discussions on the evlution of superconducting property will be made in respect to the modification of the electronic and local geometrical structures in Cu-O and/or Bi-O layers on the basis of XPS, XANES and EXAFS analyses.