A new HTSC family: the copper analogs of the single-layer Hg or Tl copper oxide superconductors

Abstract A new family of superconducting oxides has been obtained at high pressures in multiphasic samples within the Ba-Ca-Cu-O system. It corresponds to the substitution by copper of the Tl or Hg atoms in the so-called single-layer superconductors. At least four members have been detected, corresponding to n=3−6, in CuBa2Can-1CunO2n+2+x. Tc values of up to 120 K have been measured.