We report the preparation of almost phase pure (Tl0.5Pb0.5)Sr2Ca2Cu3O9, which is characterized by high temperature superconduc tivity with Tc onset=130 K, Tc midpoint=124 K, Tc zero=122.5 K as measured by electrical resistance, and a diamagnetic onset temperature, Tc mag of 124 K determined by DC magnetic susceptibility. The new procedure involves synthesizing a material with nominal stoichiometry (Tl0.5Pb0.5)Sr1.6Ca2.4Cu3O9, which is encapsulated in gold foil and sintered at 950°C for 3 h in oxyge n, then sealed in an evacuated quartz tube and finally annealed at 700∼750°C for 5∼10 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 Tl0.58(3)Pb0.38(2)Sr1.9(2)Ca2.1(1)Cu3O9 . 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.
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