Applied Physics Letters · 1987 · 61 citations · 7 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsMaterials PhysicsSolid State PhysicsElectrical ConductivityHigh-temperature MaterialsInorganic MaterialsPhase TransitionsStrongly Correlated Electron SystemsSuperconducting MaterialsCuprate SuperconductorsHigh-temperature SuperconductivityHigh-temperature SuperconductorsMetallic CharacterOxygen Partial Pressure EffectsPhase Transition TemperatureResistivityTemperature-dependent Resistivity
The resistivity of Ba2YCu3Ox was measured in the 450–850 °C range at various oxygen partial pressures. The tetragonal to orthorhombic phase transition is observed as a change in the slope of the resistivity curve. The lack of a discontinuity in the curve is consistent with the phase transition being higher than first order. It was found that decreasing the oxygen content x below 6.2 changed the resistivity of the tetragonal phase from metallic character to semiconducting character. In the metallic region of the tetragonal phase the superconducting transition temperature is depressed below 60 K, while in the semiconducting region, no superconducting onset was observed down to 6 K. In the orthorhombic phase, the resistivity of the material is shown to be governed by the number of oxygens per unit cell, suggesting that the resistivity can serve as a quality control parameter in the production of superconducting devices.
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Evidence for superconductivity above 40 K in the La-Ba-Cu-O compound system
C. W. Chu, P. H. Hor, R. L. Meng et al. · Physical Review Letters · 1987 · 1.5K citations · Full text
High T<sub>c</sub>Superconductivity of La-Ba-Cu Oxides
Shin‐ichi Uchida, H. Takagi, K. Kitazawa et al. · Japanese Journal of Applied Physics · 1987 · 490 citations