In:
Proceedings, annual meeting, Electron Microscopy Society of America, Cambridge University Press (CUP), Vol. 46 ( 1988), p. 856-857
Abstract:
It is important to combine characterization techniques such as electron microscopy with novel materials synthesis in the study of high T c superconducting phases. Results from electron microscopy studies have been correlated with structure determinations made using x-ray and neutron diffraction (1.2,3.4). Superconducting phases studied to date include YBa 2 Cu 3 O 7-x , La 1.25 Ba 1.75 Cu 3 O 7 , Bi 2 Sr 2 CuO 6 , Bi 2 Sr 2 CaCu 2 O 8 , Tl 2 Ba 2 CuO 6 Tl 2 Ba 2 CaCu 2 O 8 , and Tl 2 Ba 2 Ca 2 Cu 3 O 8 . A comparison between structures and defect populations suggests that structural defects, which modify the Cu-O arrangement (sheets or chains) intergrowths and grain boundaries, will affect superconductivity. Techniques used in this investigation include HREM, CBED, AEM, SAD and conventional imaging techniques. Samples characterized in this study were prepared in our laboratory, using both conventional and novel synthesis routes. Powder samples in the Tl-Ba-Cu-O system were prepared by heating mixtures of high purity BaO 2 , Tl 2 O 2 and CuO to 850-900°C in sealed gold tubes for 1-6 hours (3,4). Similar procedures were followed in the Bi 2 Sr 2 CaCu 2 O 8 system using Bi 2 O 3 , CaCO 3 , SrO 2 /Sr(NO 3 ) 2 and CuO. heating the mixtures in air at 700-900°C for 12-36 hours (2.4).
Type of Medium:
Online Resource
ISSN:
0424-8201
,
2690-1315
DOI:
10.1017/S042482010010634X
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
1988
SSG:
11
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