The synthesis of new phases related to YBCO by complete replacement of the chain copper sites

Author

Greaves, C. ; Slater, P.R.

Author_Institution

Sch. of Chem., Birmingham Univ., UK

Volume

27

Issue

2

fYear

1991

fDate

3/1/1991 12:00:00 AM

Firstpage

1174

Lastpage

1177

Abstract

The extent to which new phases may be synthesized by the replacement of the chain Cu sites (Cu1) in the YBa₂Cu₃O₇ structure was examined. Several new phases have been prepared, and it is demonstrated that, for cations which preferentially substitute at this site, it becomes possible to prepare phases in which the Ba cations have been totally replaced by Sr, e.g. EuSr₂Cu ₂NbO₈. All phases of this type are tetragonal, and, using Rietveld refinement techniques and powder X-ray diffraction data, it has been confirmed that the Nb occupies only the Cu1 position and adopts octahedral coordination in EuSr₂Cu₂NbO ₈. Phases involving other substituting cations are also discussed. Superconductivity has not been observed in these phases

Keywords

barium compounds; crystal atomic structure of inorganic compounds; europium compounds; high-temperature superconductors; materials preparation; phase equilibrium; strontium compounds; yttrium compounds; Cu1 position; EuSr₂Cu₂NbO₈; Rietveld refinement techniques; YBCO; YBa₂Cu₃O₇; chain Cu sites; chain copper sites; high temperature superconductors; new phases; octahedral coordination; powder X-ray diffraction; substituting cations; synthesis; tetragonal; Chemistry; Crystallography; Neodymium; Niobium; Powders; Stability; Strontium; Superconductivity; X-ray diffraction; Yttrium barium copper oxide;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.133392

Filename

133392