TY - JOUR
T1 - Reassessment of the symmetry of the 221 PbBiSrCaCuO structure using LACBED and high-resolution SAD
T2 - the relevance of Cowley's theory of disorder scattering to a real-space structural analysis
AU - Goodman, P.
AU - Miller, P.
PY - 1993/1/1
Y1 - 1993/1/1
N2 - An examination of the 221 compound of PbBiSrCaCuO using LACBED and accurately aligned high-resolution SAD patterns has led to a new assessment of its symmetry as orthorhombic in the space group Amaa, instead of monoclinic (or two-phase monoclinic and orthorhombic) as previously determined. This more accurate determination opens the way for the application of real-space methods for analysing the crystalline disorder [e.g., Cowley, Acta Cryst. A 32 (1976) 88], as an alternative to the superspace, reciprocal-space methods used in previous analyses. A brief account of the perceived gain in accuracy for both diffraction and X-ray spectroscopic analysis, resulting from the use of extended-cleavage crystals, is also given.
AB - An examination of the 221 compound of PbBiSrCaCuO using LACBED and accurately aligned high-resolution SAD patterns has led to a new assessment of its symmetry as orthorhombic in the space group Amaa, instead of monoclinic (or two-phase monoclinic and orthorhombic) as previously determined. This more accurate determination opens the way for the application of real-space methods for analysing the crystalline disorder [e.g., Cowley, Acta Cryst. A 32 (1976) 88], as an alternative to the superspace, reciprocal-space methods used in previous analyses. A brief account of the perceived gain in accuracy for both diffraction and X-ray spectroscopic analysis, resulting from the use of extended-cleavage crystals, is also given.
UR - http://www.scopus.com/inward/record.url?scp=0027715255&partnerID=8YFLogxK
U2 - 10.1016/0304-3991(93)90072-6
DO - 10.1016/0304-3991(93)90072-6
M3 - Article
AN - SCOPUS:0027715255
VL - 52
SP - 549
EP - 556
JO - Ultramicroscopy
JF - Ultramicroscopy
SN - 0304-3991
IS - 3-4
ER -