Hall-conductivity sign reversal and fluctuations in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films
- Center for Superconductivity Research, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)
We measured the longitudinal and Hall resistive transitions of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} films in applied fields up to 9 T. The longitudinal fluctuation conductivities obey the scaling behavior of the three-dimensional Hartree fluctuation theory of Ullah and Dorsey. The fluctuation Hall conductivities do not scale. Our analysis shows that there are substantial contributions from the Maki-Thompson (MT) process as well as the Aslamazov-Larkin (AL) one. Using an {ital ansatz} suggested by the microscopic theory of Fukuyama {ital et al.}, we separated the AL term from the total fluctuation conductivity. The AL Hall conductivity follows a scaling law, and the AL and MT terms have opposite sign. The sign of the AL term is consistent with the sign change in the flux-flow regime, as predicted by theory. At low fields and temperatures just above T{sub c}(H), the AL term dominates the MT term, therefore causing the total Hall-conductivity sign change. {copyright} {ital 1997} {ital The American Physical Society}
- OSTI ID:
- 496747
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 55, Issue 17; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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