Crystal growth of Bi₂Sr₂Ca₂Cu₃O_10+x and (Bi,Pb)₂Sr₂Ca₂Cu₃O_10+x by the KCl flux method

Bi₂Sr₂Ca₂Cu₃O_10+x and (Bi,Pb)₂Sr₂Ca₂Cu₃O_10+x single crystals with a sharp superconducting transition at T_c = 109 K were grown using a modified KCl flux technique. The crystals show platelike morphology with typical dimensions of 0.5 × 0.5 × 0.002 mm³ and 0.25 × 0.25 × 0.001 mm³ for Pb-free and Pb-doped compositions, respectively. The formation of Bi-2212 intergrowth in the crystals is suppressed by utilization of a stable MgO crucible, suppression of the KCl evaporation, and isothermal heat treatment at a temperature close to the melting temperature of the oxide precursor in the flux. Morphology, phase purity, and chemical composition of grown crystals were determined by various analysis methods while the superconducting properties were studied by magnetization and resistivity.