On the Origin of the Double Superconducting Transition in Overdoped YBa2Cu3Ox

Abstract

The superconducting transition in a single overdoped, detwinned YBa2Cu3Ox (YBCO) crystal is studied using four different probes. Whereas the AC and DC magnetic susceptibilities find a dominant transition at 88 K with a smaller effect near 92 K, the specific heat and electrical resistivity reveal only a single transition at 88 K and 92 K, respectively. Under hydrostatic pressures to 0.60 GPa these two transitions shift in opposite directions, their separation increasing. The present experiments clearly show that the bulk transition lies at 88 K and originates from fully oxygenated YBCO; the 92 K transition likely arises from filamentary superconductivity in a minority optimally doped phase (< 1 %) of YBCO located at or near the crystal surface.

arXiv comment9 pages, 3 figures

References in corpus (4)

• The Dependence of Tc on Hydrostatic Pressure in Superconducting MgB2
• Specific heat and magnetization of a ZrB12 single crystal: characterization of a type II/1 superconductor
• Anomalously large oxygen-ordering contribution to the thermal expansion of untwinned YBa2Cu3O6.95 single crystals: a glass-like transition near room temperature
• Evolution of the specific-heat anomaly of the high-temperature superconductor YBa2Cu3O7 under influence of doping through application of pressure up to 10 GPa

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• Pressure-induced superconductivity in elemental ytterbium metal
• Boundary states with elevated critical temperatures in Bardeen-Cooper-Schrieffer superconductors
• Microscopic derivation of superconductor-insulator boundary conditions for Ginzburg-Landau theory revisited. Enhanced superconductivity at boundaries with and without magnetic field
• Boundary effects in two-band superconductors
• Elevated critical temperature at BCS superconductor-band insulator interfaces