Structural determination of high Tc superconductor (Bi,Pb)2Sr2Ca2Cu3Ox (2223) phase with powder diffraction data
MetadataShow full item record
The link to the journal’s home page is: http://www.iop.org/EJ/journal/SUST
Copyright © 2005 Institute of Physics and IOP Publishing Limited
The (Bi,Pb)2Sr2Ca2Cu3Ox (2223) phase is regarded as the one of the most technologically significant high Tc phases in the Bi–Sr–Ca–Cu–O system. However, its structure has not been fully described so far. The definitive structure model of 2223 has been determined in this study by direct methods and Q-peak analysis of difference Fourier maps using synchrotron radiation data. Successive least squares refinement of the model with the preferred A 2aa space group was carried out by Rietveld procedures with neutron diffraction data. Anomalies were not observed for interatomic distances (bonded and non-bonded atoms), bond angles and isotropic temperature parameters. Two categories of copper atoms were clearly identified: (i) square coordinated to four oxygen atoms and (ii) pyramids with a fifth oxygen atom. The valence states of two Cu atoms have been estimated using bond valence calculations, as employed by Brown for YBCO. There is no direct bridging between the Cu squares and pyramids. The Bi3+ cations are coordinated by three oxygen atoms and form a single chain [BiO2]nn− along the a axis, which is the first report of this feature for the 2223 structure.
Showing items related by title, author, creator and subject.
Conceptual change in secondary chemistry : the role of multiple analogical models of atoms and molecules.Harrison, Allan G. (1996)Chemistry textbooks and teachers frequently use a variety of metaphors, analogies and models to describe atomic and molecular structures and processes. While it is widely believed that multiple analogical models encourage ...
Zeng, X.; Cheng, L.; Zou, J.; Ding, W.; Tian, Hu-yong; Buckley, Craig (2012)The effect of minor addition of 3d transition metals on the formation enthalpy (ΔH) and electronic structure of MgH2 have been studied using first-principle calculations, and considering the phonon-calculated zero point ...
Subaer (2004)Inorganic geopolymers or simply geopolymers based on silico-aluminate are relatively novel materials with a wide range of potential applications. The mAln purpose of the present study was to experimentally investigate the ...