Rapid synthesis of nearly-pure high Tc superconductor HgBa2CuO4+δ at ambient pressure in an open system

Abstract Nearly-pure 1201-type cuprate HgBa 2 CuO 4+δ was successfully synthesized at ambient pressure in an open system, and was characterized by powder x-ray diffraction analyses and by resistance and ac susceptibility measurements. The lattice parameters are a = 3.8742(5) A and c = 9.4798(11) A , and the T c,onset is up to 95 K. The results of the present experiment are instructive to the understanding of the formation mechanism of Hg-based superconductors, and thus to the preparation of existing Hg-based superconductors and to the search for new Hg-based high T c superconductors.