We have succeeded in obtaining single-phase samples of the Pb3201 phase (Pb2Cu)Sr0.9La1.1CuO6+δ by the modified polymerized complex method. At the first step of the synthesis, a transparent gel is found to be obtained by increasing the molar ratio of citric acid to total metal ions up to 5 without controlling the pH of the solution and without ethylene glycol. Secondly, the precursor is prepared by calcining the transparent gel. Finally, highly homogeneous samples with the onset temperature of the superconducting transition, ∼ 37 K, are obtained by sintering the precursor and subsequently annealing it. Moreover, the Pb3201 phase is found to be stable only for x = 1.1 in (Pb2Cu)Sr2-x,LaxCuO6+δ.
- Pb3201 phase
- Polymerized complex method