Structural aspects of <script type="math/tex">Bi_{2-x}Pb_{x}Sr_{3.5}Cu_{2}(CO_{3})O_{8-\delta}</script> for <script type="math/tex">0\leq x\leq0.75</script> : an electron-microscopy study

Zhang, X.F.; Van Tendeloo, G.; Amelinckx, S.; Pelloquin, D.; Michel, C.; Hervieu, M.; Raveau, B.

doi:10.1006/JSSC.1994.1378

Title

Structural aspects of $Bi_{2-x}Pb_{x}Sr_{3.5}Cu_{2}(CO_{3})O_{8-\delta}$ for $0\leq x\leq0.75$ : an electron-microscopy study

Author

Zhang, X.F.

Van Tendeloo, G.

Amelinckx, S.

Pelloquin, D.

Michel, C.

Hervieu, M.

Raveau, B.

Abstract

The structure and defect structure of Bi2-xPbxSr3.5Cu2 (CO3)O8-delta compounds with 0 less-than-or-equal-to x less-than-or-equal-to 0.75 are carefully investigated by electron diffraction and high-resolution electron microscopy. All compounds have an orthorhombic structure with a almost-equal-to b almost-equal-to 5.4 angstrom and c almost-equal-to 39.5 angstrom. The length of the b-axis decreases monotonically with increasing x. The space group for the basic structure is Abm2. The structure can be considered as an intergrowth of Bi2Sr2CuO6 lamellae with Sr2CuO2 (CO3) lamellae along the c-axis. CO3 groups behave as bridges connecting the CuO6 octahedra. In the x = 0 compound the carbon atoms are shifted away from their symmetry positions; the orientational ordering of the CO3 groups (or the carbon shift) in successive CO planes alternates along +b and -b. Typical Bi-type and Pb-type modulations are found along the b-axis up to a Pb content x = 0.5. Electron beam irradiation destroys the ordering of the CO3 groups and alters the modulated structure. (C) 1994 Academic press, inc.

Language

English

Source (journal)

Journal of solid state chemistry. - London

Publication

London : 1994

ISSN

0022-4596

DOI

10.1006/JSSC.1994.1378

Volume/pages

113 :2 (1994) , p. 327-344