The effect of the hole concentration on the superconducting property of the double CuO layer system Bi2Sr2Ca1-xYxCu2Oy (0 ≦ × ≦ 0.5) was studied. The compounds were synthesized by the polymerized complex method. The onset temperature of the superconducting transition Tc (onset) was carefully measured in terms of complex susceptibility. Tc (onset) is enhanced as x increases up to x ∼ 0.1 and then decreases as x further increases. Wet chemical analyses were carried out to determine the average charges of Bi and Cu ions. In the Bi2Sr2CaCu2Cuy compound, relatively high concentration of Bi5+ ions was detected. To interpret the results, we propose that mixed valence Bi5+/Bi3+ acts as a charge reservoir for the CuO2 planes.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering