Superlattice structures in solid solution of high-Tc YBa2Cu3O7-δ and (Pb,Cu)Sr2(Ca,Y)Cu2O7-δ superconductors

Shu-Fen Hu, R. S. Liu, D. A. Jefferson

Research output: Contribution to journalArticle

Abstract

A complete solid solution range exists between the systems YBa2Cu3O7-δ and (Pb,Cu)Sr2(Ca,Y)Cu2O7-δ has been found with general stoichiometry (Pb0.75xCu1-0.75x)(Sr2xBa 2-2x)(Ca0.5xY1-0.5x)Cu2O 7-δ. Energy dispersive spectrometry and X-ray diffraction identified that a true solid solution exists. Superlattice structures observed by electron diffraction across the solid solution range have a modulation range have a modulation periods along a* which can be varied by altering both the compositional parameter x and the overall oxygen content. The existence of these superlattices infers that the solid solution is non-random and therefore thermodynamically non-ideal. The superconducting transition temperatures, Tc, across the solid solution range are also strongly dependent on the composition, x, but no direct relationship wit h the modulation period has been established. From these studies it may be concluded that the solid solution between known superconductors is possible, although involving some partial ordering of the lattice, but ordering of cations in the rock-salt to charge reservoir layer is not a significant factor in determining the superconducting properities, which depend more closely on the overall composition and hence on the ability of the charge reservoir layer to transfer charge to the superconducting layers.

Original languageEnglish
Pages (from-to)1847-1859
Number of pages13
JournalJournal of Physics and Chemistry of Solids
Volume62
Issue number9-10
DOIs
Publication statusPublished - 2001 Oct 1

Keywords

  • A. oxides
  • C. electron microscopy
  • D. superconductivity
  • D. superlattices

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

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