Hall effect above Tc in untwinned single-crystal YBa2Cu3O7-x : normal-state behavior and superconducting fluctuations

摘要: We present a measurement of the Hall coefficient {ital R}{sub H}} for an untwinned single crystal YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}}. The was produced by method that does not involve thermomechanical detwinning, and has resistivity along copper-oxide chains only 29 {mu}{Omega} cm at 100 K, indicating high sample quality. in-plane 1/{ital become linear in temperature as T} rises significantly above T}{sub c}}. Near c}} we observe deviation from this linearity, interpret it thermodynamic fluctuations layered superconductor. Fits model to both Hall-effect data yield physically reasonable values fitting parameters. Evidence is obtained two planes each unit cell are tightly coupled, acting one superconducting layer. Surprisingly, best fits indicate dominated Maki-Thompson process rather than Aslamazov-Larkin process.