Fractal Structure Near the Percolation Threshold for YBa2Cu3O7 Epitaxial Films
| Autor: | H. Bratsberg, M. Baziljevich, M. E. Gaevski, I. A. Khrebtov, Tom H. Johansen, V.N. Leonov, Robert A. Suris, Robert Deltour, Yu. M. Galperin, D. V. Shantsev, V. E. Gasumyants, A. V. Bobyl |
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| Jazyk: | angličtina |
| Rok vydání: | 1996 |
| Předmět: |
Superconductivity
Condensed matter physics Chemistry Transition temperature General Physics and Astronomy Percolation threshold 01 natural sciences Fractal Magnetic field imaging Percolation theory Electrical resistivity and conductivity [PHYS.HIST]Physics [physics]/Physics archives 0103 physical sciences Electromagnetic shielding 010306 general physics |
| Zdroj: | Journal de Physique IV Proceedings Journal de Physique IV Proceedings, EDP Sciences, 1996, 06 (C3), pp.C3-259-C3-264. ⟨10.1051/jp4:1996339⟩ Scopus-Elsevier |
| ISSN: | 1155-4339 1764-7177 |
| DOI: | 10.1051/jp4:1996339⟩ |
| Popis: | Inhomogeneity of the properties of YBa2Cu3O7 epitaxial c-oriented films has been investigated. Using a low - temperature SEM the lateral distribution of local critical temperature has been determined with spatial resolution of 2 µm. The technique provides a direct observation of the percolative character of the superconducting transition on a microbridge scale. It is shown for the first time that near the percolation threshold the current channel has a very rough, irregular configuration and the fractal dimensionality of the superconducting cluster is estimated as 1.55. The magnetic field imaging of samples is carried out and a quantitative correlation between Tc-map and the map of critical density of shielding currents is observed. The transition curves R(T) over a wide range of resistances and bias currents are described in terms of the network model. The model takes into account both the spatial distribution of Tc and the presence of random weak links with a wide distribution of their critical currents. |
| Databáze: | OpenAIRE |
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