SYNTHESIS OF NEARLY-PURE 2223 PHASE Tl2Ba2Ca2Cu3O10 WITH Tc ABOVE 120 K FROM 2223 STARTING COMPOSITION

Nearly-pure 2223 phase Tl2Ba2Ca2Cu3O10 with zero-resistance temperature of 120 K or higher was synthesized for the first time from 2223 starting composition using a Ba2Ca2Cu3O7 precursor method in a half-closed system. The results from resistance and ac susceptibility measurements and powder X-ray diffraction analyses are presented. The optimal preparation condition is heating at about 900° C for about 48 hours. This optimal condition actually produces the true composition of the “2223” phase.