| Autor: |
J.-Y. Prieur, M. Stenger, J. Joffrin, T. Königs, G. Ockenfuß, Roger Wördenweber, M. Reese, C. Barre |
| Rok vydání: |
1996 |
| Předmět: |
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| Zdroj: |
Solid State Communications. 98:777-780 |
| ISSN: |
0038-1098 |
| Popis: |
In order to change the oxygen content of YBa 2 Cu 3 O 7−δ thin films, we have measured the YBCO c-axis length “in situ” by X-ray analysis while heating the films in a flow of 10 mbar of molecular oxygen. We observed two kinds of c-axis length variation: a reversible one associated with the temperature and composition independent expansion coefficient which was determined to be α c = 23·10 −6 K −1 , and an irreversible variation that appeared when the substrate was heated above 200°C. The latter is attributed to oxygen loss. The timescale of the oxygen effusion strongly depends on the morphology of the YBa 2 Cu 3 O 7−δ -film, i.e. films with rough surface loose oxygen much quicker than smooth films. Therefore, in order to obtain films in a controlled way, it is necessary to observe the c-axis length continuously during the preparation. The c-axis length and the superconducting critical temperature are used to determine the oxygen deficiency δ. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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