Fluctuation conductivity and microscopic granularity in bi-based high-temperature superconductors

Visualizar/abrir
Data
1997Autor
Tipo
Abstract
Systematic conductivity measurements near Tc in granular (Bi,Pb)-Sr-Ca-Cu-O superconductors are presented, and focus is given on the interplay between thermal fluctuations and disorder at micro- and mesoscopic levels. Experiments show that the resistive transition is a two-step process. In the normal phase, Gaussian and critical fluctuation conductivity regimes were identified. Both are affected by local disorder. Particularly, the critical regime is characterized by a power law with exponent λ ...
Systematic conductivity measurements near Tc in granular (Bi,Pb)-Sr-Ca-Cu-O superconductors are presented, and focus is given on the interplay between thermal fluctuations and disorder at micro- and mesoscopic levels. Experiments show that the resistive transition is a two-step process. In the normal phase, Gaussian and critical fluctuation conductivity regimes were identified. Both are affected by local disorder. Particularly, the critical regime is characterized by a power law with exponent λcr~3, which we interpret as resulting from microscopic granularity. Below Tc and in the regime describing the approach to the zero-resistance state, fluctuation conductivity diverges as expected in a paracoherent-coherent transition of a mesoscopic granular superconductor. The results show that, instead of trivially rounding the transition, disorder at micro- and mesoscopic levels preserves a true critical phenomenology in granular superconductors. ...
Contido em
Physical review. B, Condensed matter. New York. Vol. 56, no. 22 (Dec. 1997), p. 14815-14821
Origem
Estrangeiro
Coleções
-
Artigos de Periódicos (42116)Ciências Exatas e da Terra (6311)
Este item está licenciado na Creative Commons License
