Physical Review Letters · 1987 · 349 citations · 11 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsMaterials PhysicsSolid State PhysicsCurie TemperatureMagnetic Properties Of SolidsMagnetism In SolidsPhase TransitionsStrongly Correlated Electron SystemsSuperconducting MaterialsCurie-weiss LawHigh-temperature SuperconductivityHigh-temperature SuperconductorsMeissner EffectSuperconducting Critical TemperatureSuperconducting Phase TransitionsSuperconducting PropertiesX-ray Diffraction Analysis
Transition to a superconducting zero-resistance state at 155 K is observed for the first time in bulk material. A new five-element compound has been synthesized with nominal composition ${\mathrm{Y}}_{1}$${\mathrm{Ba}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{F}}_{2}$${\mathrm{O}}_{\mathrm{y}}$@B. Fluorine plays a critical role in achieving this effect. X-ray diffraction and electron microprobe analysis indicate that the samples are multiphasic. Evidence is presented that the samples contain superconducting phases with onset temperatures considerably above 155 K. Magnetic measurements suggest a flux-trapping effect below 260 K, and diamagnetic deviations from Curie-Weiss behavior in the range 250 K\ensuremath{\le}T\ensuremath{\le}100 K indicate a Meissner effect in a small superconducting volume fraction.
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High-pressure study of the new Y-Ba-Cu-O superconducting compound system
P. H. Hor, Li Gao, R. L. Meng et al. · Physical Review Letters · 1987 · 383 citations
Observation of the Reverse ac Josephson Effect in Y-Ba-Cu-O at 240 K
J. T. Chen, L. E. Wenger, C. J. McEwan et al. · Physical Review Letters · 1987 · 146 citations