Synthesis of Hg-based cuprate superconductors $HgBa_{2}Ca_{n-1}Cu_{n}O_{2(n+1)+\delta}$ by CsCl flux additional method

Abstract

We have succeeded in the synthesis of Re-doped $HgBa_{2}Ca_{n-1}Cu_{n}O_{2(n+1)+\delta}$ quickly by a sealed tube technique with a bit of CsCl flux. Powder X-ray diffraction measurement revealed that the single phases of Re-doped $HgBa_{2}CuO_{4+\delta}$ (Hg1201), $HgBa_{2}CaCu_{2}O_{6+\delta}$ (Hg1212), and $HgBa_{2}Ca_{2}Cu_{3}O_{8+\delta}$ (Hg1223) formed in 4 h. The sample grains exhibited plate-like crystals with the sizes of 20$\times$20$\times$1 $\mu m^{3}$ and the chemical compositions of Hg1201, Hg1212, and Hg1223. The superconducting transitions were observed at 25 K for Hg1201, 122 for Hg1212, and 133 K for Hg1223 in the magnetic susceptibility. These results indicate that the developed method is useful for the fabrication of Hg-based superconducting wires.