Superconductivity in the indium-doped Tl-1223 phase: (Tl0.8In0.2)(Sr0.8Ba0.2)(2)Ca2Cu3O9-delta

We report the synthesis and characterization of a new Tl- and In-based '1223' type cuprate oxide, (Tl0.8In0.2)(Sr0.8Ba0.2)(2)Ca2Cu3O9-delta (Tl,In-1223). The as-synthesized Tl,In-1223 compound becomes superconducting at about 80 K, The T-c increased to 103 K when the sample was annealed under an argon atmosphere, Magnetization studies on polycrystalline samples of Tl,In-1223 reveal that persistent current densities (J(p)) of the indium-doped compound are about 10 times smaller than those of corresponding TI,Bi-1223 and Tl,Pb-1223 with the same structure type, Small substitution of In for Tl in Tl-1223 results in a large reduction of T-c and J(p), A slight change in the electronic configurations of the rock-salt metal sites appears to affect the delicate balance of the metal and oxygen energy levels, which leads to the virtual changes in the superconductivity in Tl,In-1223.