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Incorporation of microabsorption corrections into Rietveid analysis

Published online by Cambridge University Press:  10 January 2013

W. Pitschke ,
N. Mattern  and
H. Hermann
W. Pitschke
Affiliation:
Institute of Solid State and Materials Research Dresden, PF, D-01171 Dresden, Germany
N. Mattern
Affiliation:
Institute of Solid State and Materials Research Dresden, PF, D-01171 Dresden, Germany
H. Hermann
Affiliation:
Institute of Solid State and Materials Research Dresden, PF, D-01171 Dresden, Germany
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Abstract

Surface roughness of planar samples causes an additional attenuation of X-ray diffraction intensity measured in Bragg–Brentano geometry. The decrease of intensity becomes stronger with decreasing scattering angle. This is part of the microabsorption effect. Two quantitative expressions describing the microabsorption effect are incorporated into the DBWS 9006-PC Rietveid program [D. B. Wiles and R. A. Young, J. Appl. Crystallogr. 15, 149–151 (1981)]. The procedure is applied to scattering data obtained from YBa2Cu3O7-powder samples with different degree of surface roughness but approximately identical bulk structure. The procedure is proved to work well. However, the values obtained for the parameters of the temperature factors and the microabsorption effect are correlated, and careful discussion is necessary to interpret the results.

Keywords

microabsorptionsurface roughnessRietveid analysisstructure refinement
Type
Research Article
Information
Powder Diffraction , Volume 8 , Issue 4 , December 1993 , pp. 223 - 228
Copyright
Copyright © Cambridge University Press 1993

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References

Brindley, G. W. (1945). “The effect of grain or particle size on X-ray reflections from mixed powders and alloys, considered in relation to the quantitative determination of crystalline substances by X-ray methods,” Philos. Mag. 36, 347–369.CrossRefGoogle Scholar
Brodt, K., Fuess, H., Paulus, E. F., Assmus, W., and Kowalewski, J. (1990). “Untwinned single crystals of the high-temperature superconductor YBa2Cu3O7−x,” Acta Crystallogr. C 46, 354–358.Google Scholar
de Wolff, P. M. (1956). “Measurement of particle absorption by X-ray fluorescence,” Acta Crystallogr. 9, 682–683.CrossRefGoogle Scholar
Dollase, W. A. (1986). “Correction of intensities for preferred orientation in powder diffractometry: Application of the March model,” J. Appl. Crystallogr. 19, 267–272.CrossRefGoogle Scholar
Harrison, R. J., and Paskin, A. (1964). “The effects of granularity on the diffracted intensity in powders,” Acta Crystallogr. 17, 325–331.CrossRefGoogle Scholar
Hermann, H., and Ermrich, M. (1987). “Microabsorption of X-ray intensity in randomly packed powder specimens,” Acta Crystallogr. A 43, 401–405.CrossRefGoogle Scholar
Hermann, H., and Ermrich, M. (1989). “Microabsorption correction of X-ray intensities diffracted by multiphase powder specimens,” Powder Diffr. 4, 189–195.CrossRefGoogle Scholar
Hewat, A. W. (1973). “Cubic-tetragonal-orthorhombic-rhombohedral ferroelectric transitions in perovskite potassium niabate: neutron powder profile refinement of the structures,” J. Phys. C 6, 2559–2572.Google Scholar
Izumi, F., Asano, H., Ishigaki, T., Takayama-Muromachoi, E., Uchida, Y., Watanabe, N., and Nishikawa, T. (1987). “Rietveld refinement of the structure of Ba2YCu3O7−x with neutron powder diffraction data,” Jpn. J. Appl. Phys. 26, L649–L651.CrossRefGoogle Scholar
Kumar, R., Sparks, C. J., Shiraishi, T., Specht, E. D., Zschack, P., Ice, G. E., and Hisatsune, K. (1991). “X-ray determination of site occupation parameters in ordered ternaries Cu(AuxM1−x)M = Ni,Pd,” Mat. Res. Soc Symp. Proc. 213, 369–374.CrossRefGoogle Scholar
March, A. (1932). “Mathematische Theorie der Regelung nach der Korngestalt bei affiner Deformation,” Z. Kristallogr. 81, 285–297.CrossRefGoogle Scholar
Masciocchi, N., Toraya, H., and Parrish, W. (1991). “A theta-dependent error present in powder data of highly absorbing materials: a surface roughness effect?,” Materials Science Forum 79–82, 245–250.CrossRefGoogle Scholar
Pitschke, W., Hermann, H., and Mattern, N. (1993). “The influence of surface roughness on diffracted X-ray intensities in Bragg-Brentano geometry and its effect on the structure determination by means of Rietveld analysis,” Powder Diffr. 8, 74–83.CrossRefGoogle Scholar
Rietveld, H. M. (1967). “Line profiles of neutron powder diffraction peaks for structure refinement,” Acta Crystallogr. 22, 151–152.CrossRefGoogle Scholar
Rietveld, H. M. (1969). “A profile refinement method for nuclear and magnetic structures,” J. Appl. Crystallogr. 2, 65–71.CrossRefGoogle Scholar
Sparks, C. J., Kumar, K., Specht, E. D., Zschack, P., and Ice, G. E. (1991). “Effect of powder sample granularity on fluorescent intensity and on thermal parameters in X-ray diffraction Rietveld analysis,” Adv. X-ray Anal. 35, 57–60.Google Scholar
Suortti, P. (1972). “Effects of porosity and surface roughness on the X-ray intensity reflected from a powder specimen,” J. Appl. Crystallogr. 5, 325–331.CrossRefGoogle Scholar
Toraya, H. (1986). “Whole-powder-pattern fitting without reference to a structural model: Application to X-ray powder diffractometer data,” J. Appl. Crystallogr. 19, 440–444.CrossRefGoogle Scholar
Wiles, D. B., and Young, R. A. (1981). “New computer program for Rietveld analysis of X-ray powder diffraction patterns,” J. Appl. Crystallogr. 15, 149–151.CrossRefGoogle Scholar
Will, G., Parrish, W., and Huang, T. C. (1983). “Crystal structure refinement by profile fitting and least-squares analysis of powder diffractometer data,” J. Appl. Crystallogr. 16, 681–622.CrossRefGoogle Scholar
Williams, A., Kwei, G. H., Von Dreele, R. B., Larson, A. C., Raistrick, I.D., and Bish, D. L. (1988). “Joint X-ray and neutron refinement of the structure of superconducting YBa2Cu3O7−x: Precise structure, anisotropic thermal parameters, strain, and cation disorder,” Phys. Rev. B 7, 7690–7692.Google Scholar
Young, R. A., and Wiles, D. B. (1982). “Profile shape functions in Rietveld analysis,” J. Appl. Crystallogr. 15, 430–438.CrossRefGoogle Scholar
Young, R. A. (Ed.) (1993). The Rietveld Method (Oxford U.P., New York), 1 p.CrossRefGoogle Scholar