Bulk superconductivity in the new orthorhombic (Tl, Pb)-Ca-Sr-Cu-O system

[[abstract]]Bulk superconducting phases with compositional ratios (2122) and (2021) in the new (Tl, Pb)-Ca-Sr-Cu oxide system were reported. A two-step superconducting transition with onset temperatures of 118 K and 88 K were observed from electrical resistivity measurements. Magnetic susceptibility data indicate that bulk transition starts at 112 K. Superconductivity is highly reproducible and more stable than its Tl-Ca-Ba-Cu oxide homologs. Powder X-ray diffraction profiles and EDAX analysis indicate the existence of two orthorhombic (pseudotetragonal) phases with c=29.08 Å (Bi2CaSr2Cu2O8-type) and c=24.09 Å (Bi2Sr2CuO6-type) with a possible incommensurate superstructure along the b-axis[[fileno]]2010102010040[[department]]物理