CBED AND SAED STUDY OF HIGH Tc Ba-Y-Cu-O SUPERCONDUCTORS
- 1 June 1987
- journal article
- Published by World Scientific Pub Co Pte Ltd in Modern Physics Letters B
- Vol. 1 (3) , 67-71
- https://doi.org/10.1142/s0217984987000107
Abstract
We have studied two kinds of superconducting samples of Tc about 90K with nominal compositions Ba3Y2Cu5O12+x and Ba0.5Y4.5Cu5O12+x, respectively, by means of convergent beam electron diffraction (CBED) and selected area electron diffration (SAED) in more detail. The common phase has been found to be a pseudotetragonal superstructure based on a cubic perovskite subcell of a=0.39 nm. Its lattice parameters are a=ap, c=3ap and its space group is Pmmm. This phase is considered to be responsible for the superconductivity at about 90K. This is the major phase in Ba3Y2Cu5O12+x, but the minor phase in Ba0.5Y4.5Cu5O12+x. The lattice parameters and the symmetry of the other phases in Ba0.5Y4.5Cu5O12+x have also been determined.Keywords
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