Formation conditions of the (2223) phase in lead-substituted superconducting ceramics BiSrCaCuO

Role of lead in the growth of the highT c phase in the Bi2−x Pb x Sr2Ca2Cu3O y systems

“…Our d values and intensities of the peaks also coincided with those reported by Chavira et al (1988) for the Bil.sPbo.2Ca2Sr2Cu30 r compound in which they have obtained a To(0) at 106 K. Lattice parameters of these high Tc 2223 (110 K) phase have been determined by them and are a = 5"41, b = 5"42A and c = 37.0A. Pierre et al (1989) indexed the 2223 phase with reference to an orthorhombic cell having the lattice constants a~-b-~5"4A and c-~37A. Xianhui et al (1989) obtained T~(0) at 105K in a Bi2.sPbo.sCa2Sr2Cu3Oy sample and obtained values of the predominant diffraction peaks at 3"708 A, 3.089 A and 2.652 A.…”

“…A broad agreement both in the d values and the intensity ratios of prominent peaks viz. 1 1 3, 1 1 5, 1 1 7, 200and 2 20was found with the values reported by Hazen et al (1988), Chavira et al (1988) and Pierre et al (1989). These are shown in table 1 along with the data of Hazen et al (1988) who determined the lattice constants assuming the structure to be orthorhombic and obtained the cell parameter values, a = 5"41 A, b = 5.439 A and c = 30"78 A.…”

“…They have also done computer-stimulated spectra for this 2122 (80 K) phase by using Fmmm, Cccm and lmmm space groups respectively and found that Fmmm was the best choice. Pierre et al (1989) obtained a ~-b ~ 5"4A and c ~-30"8 A. It is thus clear that Bi2Ca2Sr2Cu30 r predominantly contains the 2122 phase.…”

Effects of Sb and Pb doping on the high-Tcphase-formation in Bi-Sr-Ca-Cu-O superconductors

“…This is partly because a large al [32] have found that the optimum ratio of Pb/Bi is 0.5/1.85, besides 75% of Pb doped initially are lost during the heat treatment. Pierre et a1 [35] argued that the optimal ratio of initial Bi content to Pb content was…”

Effect of annealing and quenching on superconductivity in Pb and Sb-doped Bi2Sr2Ca2Cu3O x

“…Zero resistance at 132K was reported (Liu et al 1989) in the multiphase system of Bil.q_~Pb~Sbo.lSr2Ca2Cu30 r Despite numerous reports in literature on the bismuth compounds, there are differences in the composition, values of the transition temperature and the lattice parameters. For example, it was reported (Torrance et al 1988) that the 2212 composition is tetragonal with lattice parameters a = b = 0-3821 nm and c = 3"066 nm, whereas the same sample has been reported (Pierre et al 1989) to be orthorhombic with a ~ b ~ 0.54 nm and c ~ 3-08 nm. Similarly, the 110 K phase was reported to be orthorhombic with a = 0"5420 nm, b = 0.5447 nm and c = 3.6804 nm, while it was reported to possess the tetragonal structure (Pissas et al preprint) having a = 0-3821 nm and c --3"7034 nm.…”