Gaussian, three-dimensional-XY, and lowest-Landau-level scalings in the low-field fluctuation magnetoconductivity of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}
- Instituto de Fisica, Universidade Federal do Rio Grande do Sul, P.O. Box 15051, 91501-970 Porto Alegre (Brazil)
- Instituto de Fisica, Universidade Federal do Rio de Janeiro, P.O. Box 68528, 21945-970 Rio de Janeiro (Brazil)
- Facultad de Ciencias Geologicas, UCM, 28040 Madrid (Spain)
- Instituto de Ciencias de Materiales, CSIC, Cantoblanco, 28049 Madrid (Spain)
Systematic measurements of low-field fluctuation magnetoconductivity in a single crystal of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} are reported. Gaussian, critical, and lowest-Landau-level scalings are observed. In the Gaussian regimes, large intervals corresponding to low-dimensional fluctuations are evidenced. Far above T{sub c}, effects of disorder produces a fluctuation spectrum characterized by a fractal topology. Decreasing the temperature, at first a homogeneous two-dimensional behavior is observed. Then, near T{sub c} a crossover occurs to a narrow three-dimensional (3D) mean-field regime. Still closer to T{sub c}, a scaling consistent with the predictions of the full dynamic 3D-XY universality class is clearly evidenced. This genuine critical regime is destroyed upon the application of magnetic fields above a few mT. For fields above a certain limit and in large temperature intervals, fluctuation magnetoconductivity scales as predicted by the lowest-Landau-level approximation of the Ginzburg-Landau theory. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 544909
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 56, Issue 17; Other Information: PBD: Nov 1997
- Country of Publication:
- United States
- Language:
- English
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