Europhys. Lett.
Volume 48, Number 1, October 1999
Page(s) 79 - 85
Section Condensed matter: electronic structure, electrical, magnetic and optical properties
Published online 01 September 2002
DOI: 10.1209/epl/i1999-00117-6

Europhys. Lett, 48 (1), pp. 79-85 (1999)

Relaxation time of the Cooper pairs near ${{T_{\rm c}}}$ in cuprate superconductors

M. V. Ramallo, C. Carballeira, J. Viña, J. A. Veira
T. Mishonov, D. Pavuna and F. Vidal

Laboratorio de Bajas Temperaturas y Superconductividad
Departamento de Física de la Materia Condensada
Universidad de Santiago de Compostela
Santiago de Compostela, E-15706 Spain

(received 14 June 1999; accepted 2 August 1999)

PACS. 74.40$\rm +k$ - Fluctuations (noise, chaos, nonequilibrium superconductivity, localization, etc.).
PACS. 74.72Bk - Y-Based cuprates.
PACS. 74.20$\rm -z$ - Theories and models of superconducting state.


It is first shown that the thermal fluctuation effects on the transport and on the thermodynamic observables above the superconducting transition may provide, when they are analyzed simultaneously and consistently, a powerful tool to access the relaxation time, ${{\tau_0}}$, of the Cooper pairs with wave vector ${\rm\bf k}=0$ in high-temperature cuprate superconductors (HTSC). Then, we apply this procedure to optimally doped YBa2Cu3O$_{7-\delta}$ (Y-123) crystals. It is found that in this HTSC ${{\tau_0}}$ follows, within 20% accuracy, the BCS temperature behaviour and amplitude given by ${{\tau_0}}=\pi\hbar/[8{{k_{\rm B}}}(T-{{T_{\rm c0}}})]$.


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