ISSN:
1572-9605
Keywords:
La2−x Sr x CuO4
;
redox process
;
transition temperature
;
superconductor
Source:
Springer Online Journal Archives 1860-2000
Topics:
Electrical Engineering, Measurement and Control Technology
,
Physics
Notes:
Abstract A series of oxidized La2−x Sr x CuO4+y $$(0.05 \preccurlyeq x \preccurlyeq 0.3)$$ compounds has been prepared by treating the starting materials with a solution of Br2 in NaOH at room temperature. The structural modifications due to the oxidation of the materials have been studied by X-ray diffraction. Some of the observed changes are: (i) a large increase in the long parameter of the unit cell for samples with Sr content $$0.05 \preccurlyeq x \preccurlyeq 0.15$$ and (ii) a slight decrease in a along the whole range ofx. Interesting features have been observed regarding the critical temperatures of these materials: transition temperatures are higher for those containing lower Sr amounts (some of them were even nonsuperconducting before the oxidation treatment) in contrast to materials with x≻0.15, whoseT c's do not change very much. The influence of both oxygen and strontium contents on the structural modifications and the superconducting properties of the oxidized materials will be discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00732270
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