On the consequences of the uncertainty principle on the superconducting fluctuations well inside the normal state
| Autor: | J. Viña, Carlos Carballeira, S. R. Currás, J.A. Veira, Félix Vidal, Manuel V. Ramallo, Jesús Mosqueira |
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| Rok vydání: | 2002 |
| Předmět: |
Superconductivity
Physics Uncertainty principle Condensed matter physics Condensed Matter - Superconductivity FOS: Physical sciences General Physics and Astronomy Thermal fluctuations Superconductivity (cond-mat.supr-con) Superfluidity Magnetization Electrical resistivity and conductivity Condensed Matter::Superconductivity Cooper pair Coherence (physics) |
| Zdroj: | Europhysics Letters (EPL). 59:754-760 |
| ISSN: | 1286-4854 0295-5075 |
| DOI: | 10.1209/epl/i2002-00190-3 |
| Popis: | We first argue that the collective behaviour of the Cooper pairs created by thermal fluctuations well above the superconducting transition temperature, Tc, is dominated by the uncertainty principle which, in particular, leads to a well-defined temperature, T^C, above which the superconducting coherence vanishes. On the grounds of the BCS approach, the corresponding reduced-temperature, ln(T^C/Tc), is estimated to be around 0.55, i.e., above T^C \approx 1.7Tc coherent Cooper pairs cannot exist. The implications of these proposals on the superfluid density are then examined using the Gaussian-Ginzburg-Landau approximation. Then we present new measurements of the thermal fluctuation effects on the electrical conductivity and on the magnetization in different low- and high-Tc superconductors with different dopings which are in excellent agreement with these proposals and that demonstrate the universality of ln(T^C/Tc). LaTeX, 10 pages, 3 figures, as published in Europhysics Letters |
| Databáze: | OpenAIRE |
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