In:
International Journal of Modern Physics B, World Scientific Pub Co Pte Ltd, Vol. 01, No. 02 ( 1987-06), p. 291-294
Abstract:
The structure of high Tc(88.7K) superconductor YBa 2 Cu 3 O 7−δ has been studied at room temperature as well as at a temperature slightly below transition temperature by neutron powder diffraction technique. The room temperature data has been analysed using powder profile refinement based on the space group Pmmm. The structure parameters from the profile refinement are: lattice constants a=3.8033A, b=3.8737A , c=11.6275A with Y at 1h(0.5 0.5 0.5), Ba at 2t(0.5 0.5 0.1882), Cu-1 at 1a(0 0 0), Cu-2 at 2q(0 0 0.3565), O-1 at 2q(0 0 0.1600), O-2 at 2s(0.5 0 0.3767), O-3 at 2r(0 0.5 0.3795), O-4 at 1e(0 0.5 0) and O-5 at 1b(0.5 0 0). All sites except 2s, 1b, 1e are fully occupied; the refined populations for 2s, 1b, 1e are 1.74, 0.42, and 0.69 respectively, with R p =8.40 , R I =5.21 . Thus, we get an oxygen deficiency δ=0.14 . It seems that no evidence for structural phase transition accompanying the superconducting transition was observed.
Type of Medium:
Online Resource
ISSN:
0217-9792
,
1793-6578
DOI:
10.1142/S0217979287000359
Language:
English
Publisher:
World Scientific Pub Co Pte Ltd
Publication Date:
1987
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