New high-Tc superconducting intercalation compound

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作者：

Seoul Natl Univ, Seoul, Korea, Republic of ^{[1
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来源：

Synth Met | / 1 -3 pt 3卷 / 1551-1553期

关键词：

Bismuth compounds - Charge transfer - Crystal lattices - Expansion - High temperature superconductors - Iodine - Magnetic permeability measurement - Silver compounds - Superconductivity - Thermogravimetric analysis - X ray crystallography - X ray spectroscopy;

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摘要：

A new high-Tc superconducting intercalation compound, AgIBi2Sr2CaCu2Oy, has been prepared either by reacting the silver metal directly with Bi2Sr2CaCu2Oy powders under P(I2) approx. 1 atm. at 190°C or by the intercalation reaction between the iodine-intercalated Bi2Sr2CaCu2Oy and AgI. According to the X-ray diffraction analysis, the observed basal increase of 7.35 angstrom upon silver iodide intercalation indicates that the lattice expansion for AgIBi2Sr2CaCu2Oy is twice as large as that for the first-staged iodine-intercalated Bi2Sr2CaCu2Oy (Δd 3.6angstrom). Such a result suggests the gallery contains a double layer of iodine. A slight decrease in Tc for the AgIBi2Sr2CaCu2Oy (Tc 63K) compared to the pristine (Tc 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 Tc 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.

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