A new high-T c superconducting intercalation compound, AgIBi 2 Sr 2 CaCu 2 O y , has been prepared either by reacting the silver metal directly with Bi 2 Sr 2 CaCu 2 O y powders under P(I 2 ) ∼ 1atm. at 190°C or by the intercalation reaction between the iodine-intercalated Bi 2 Sr 2 CaCu 2 O y and AgI. According to the X-ray diffraction analysis, the observed basal increase of 7.35 Å upon silver iodide intercalation indicates that the lattice expansion for AgIBi 2 Sr 2 CaCu 2 O y is twice as large as that for the first-staged iodine-intercalated Bi 2 Sr 2 CaCu 2 O y (Δd = 3.6 A ̊). Such a result suggests the gallery contains a double layer of iodine. A slight decrease in T c for the AgIBi 2 Sr 2 CaCu 2 O y (T c ≈ 63K) compared to the pristine (T c ≈ 76K) has been observed by the d.c magnetic susceptibility measurements. The X-ray absorption spectroscopic results show that there is no charge-transfer between guest species (AgI) and host lattice. It confirms again that interblock-coupling has little effect on the superconductivity, since the T c is not significantly evolved upon AgI intercalation with a large lattice expansion along the c-axis which is perpendicular to the (Cu-O) superconducting layers.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry