Simultaneous dysprosium- and lead-substituted high-Tc superconductor bismuth cuprates
Por:
Schieber M., Friedman M., Levinsky M., Zhou B.L., Reyes Gasga J., Van Tendeloo G., Amelinckx S.
Publicada:
1 ene 1990
Resumen:
The introduction of small amounts of Dy in ceramic BiSrCaCuO (BSCCO) with nominal composition of Bi2Sr2Ca1-xDy xCu2O8+z, Bi2Sr2Ca 2-xDyxCu3O10+z, and Bi 1.6Pb0.4Sr2Ca2-xDy xCu3O10+z with 0.1<x<0.3 was studied in both stoichiometric and nonstoichiometric compositions where the nonstoichiometric composition was used to aid the sintering process in order to obtain a maximum Tc and contained excesses of CaO and CuO. It was found that regardless of the sintering conditions and starting compositions only the Bi:Sr:Ca:Cu=2:2:1:2 (2212) phase was produced. The highest Tc (R=0) in the Dy-substituted sample obtained was 84 K and this was obtained only for the nonstoichiometric composition Bi1.6Pb0.4Sr 2Ca2.5Dy0.3Cu3.5Ox which contained mostly the 2212 phase together with tiny amounts of Bi 2Sr2Ca2Cu3Ox (2223) phase. High-resolution electron microscopy data performed on Bi 1.6Pb0.4Sr2Ca2.5Dy 0.3Cu3.5010+z show that the introduction of Dy in the original 2223 Pb-containing phase caused only the formation of the 2212 phase without changing the modulated structure known to occur in the substituted Bi and Sr BSCCO compounds confirming also earlier suggestions made by Tarrascon et al. [Phys. Rev. B 2, 4316 (1989)] that the rare-earth cations stabilize the 2212 phase and substitute only for Ca and not for the Sr or Bi sites in the 2212 phase.
Filiaciones:
Schieber M.:
Xsirius Superconductivity Materials, 7590 East Gray Road, Scottsdale, AZ 85460, United States
School of Applied Science, Hebrew University of Jerusalem, Jerusalem, Israel
Friedman M.:
School of Applied Science, Hebrew University of Jerusalem, Jerusalem, Israel
Xsirius Superconductivity Materials, P. O. Box 23566, Har Hahotsvim, Jerusalem 91230, Israel
Levinsky M.:
Xsirius Superconductivity Materials, P. O. Box 23566, Har Hahotsvim, Jerusalem 91230, Israel
Zhou B.L.:
Xsirius Superconductivity Materials, 7590 East Gray Road, Scottsdale, AZ 85460, United States
Reyes Gasga J.:
University of Antwerp (RUCA), Groenenborgerlaan 171, B-2020 Antwerp, Belgium
Van Tendeloo G.:
University of Antwerp (RUCA), Groenenborgerlaan 171, B-2020 Antwerp, Belgium
Amelinckx S.:
University of Antwerp (RUCA), Groenenborgerlaan 171, B-2020 Antwerp, Belgium
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