Superconductivity at 124 K in (Tl, Pb)Sr2Ca2Cu3O9

✍ Scribed by R.S. Liu; S.F. Hu; D.A. Jefferson; P.P. Edwards

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 338 KB
• Volume: 198
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(92)90207-s

✦ Synopsis

We report the preparation of almost phase pure (T10.sPbo.s)Sr2Ca2Cu3Og, which is characterized by high temperature superconductivity with T¢onset= 130 K, Tcmidpoint= 124 K, Tczero= 122.5 K as measured by electrical resistance, and a diamagnetic onset temperature, Tcm~ of 124 K determined by DC magnetic susceptibility. The new procedure involves synthesizing a material with nominal stoichiometry (Tlo.sPbo.5)Srl.6Ca2.4Cu3Og, which is encapsulated in gold foil and sintered at 950°C for 3 h in oxygen, then sealed in an evacuated quartz tube and finally annealed at 700~ 750°C for 5 ~ l0 days. From the results of X-ray diffraction and energy-dispersive X-ray spectrometry (EDS), we have identified the phase responsible for the superconductivity in the annealed sample to be Tlo.sa(3)Pbo.3s(2)Srt.9t2)Ca2.~ o)Cu309. No superlattice and intergrowth along the a* and c* directions were observed but streaks along the c*-axis were found from microcrystallites of the annealed sample.