The high-${\mathit{T}}_{\mathit{c}}$ (110-K) superconducting phase in the Pb-Bi-Sr-Ca-Cu-O has been isolated and its structural and physical properties investigated. Transmission-electron-microscopy results show that the structure belongs to a monoclinic system that is different from reports by other groups and in agreement with our x-ray-diffraction analysis. The refined crystal data are a=3.779 Å, b=3.834 Å, c=37.150 Å, α=β=90°, γ=90° 51’, V=538.5 A${\mathrm{̊}}^3$, space group I112. Based on the resistivity, magnetization, critical-field, and specific-heat measurements, various parameters characterizing the monophase superconductors were determined or derived. Some of them are listed as follows: ${\mathit{T}}_{\mathit{c}\mathit{e}}$ (endpoint)=107 K, ${\mathit{T}}_{\mathit{c}\mathit{m}}$ (midpoint)=110 K, ΔC (specific heat jump at 107 K)=5.3 J/mol K, γ (the Sommerfeld constant) =34.6 mJ/mol ${\mathrm{K}}^2$, FTHETA (Debye temperature)=418 K, ${\mathit{H}}_{\mathit{c}1}$(0)=900 G, ${\mathit{H}}_{\mathit{c}2}$(0)=184 T, and ${\mathit{J}}_{\mathit{c}}$(1.5 K, 0 T)=4.8×${10}^4$ A/${\mathrm{cm}}^2$, etc. Morphology, thermal analysis, and pressure effects of the sample are also mentioned.

• Received 2 October 1989

DOI:https://doi.org/10.1103/PhysRevB.41.6541