✦ LIBER ✦

Application of convergent beam electron diffraction in the structural study of high-temperature superconducting oxides

✍ Scribed by Zou, X. D. ;Yang, C. Y. ;Zhou, Y. Q.

Publisher: Wiley (John Wiley & Sons)
Year: 1987
Tongue: English
Weight: 646 KB
Volume: 7
Category: Article
ISSN: 0741-0581
DOI: 10.1002/jemt.1060070405

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✦ Synopsis

Convergent beam electron diffraction (CBED) is a powerful technique for symmetry study of crystal. It has widespread application in physics and material sciences, as demonstrated in a recent superconducting oxide study. Using this technique, we have studied Ba-La-Cu-O superconductors with a transition temperature of about 40 degrees K and Ba-Y-Cu-O superconductors with a critical temperature (Tc) of about 90 degrees K. We have found that in Ba-La-Cu-O superconductors the superconducting phase La2-xBaxCuO4-y has a distorted K2NiF4-type structure and the space group Fmmm. The two other phases in Ba-La-Cu-O superconductors have also been studied. In our Ba-Y-Cu-O superconductors, the Ba2YCu3O7-x compound, which is responsible for 90 degrees K superconductivity, has two different space groups: An orthorhombic space group Pmmm and a tetragonal space group P4mm or P4/mmm.

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