Hostname: page-component-745bb68f8f-cphqk Total loading time: 0 Render date: 2025-01-15T07:13:42.899Z Has data issue: false hasContentIssue false
  • English
  • Français

Extended X-Ray Absorption Fine Structure study of Potassium Niobate

Published online by Cambridge University Press:  21 February 2011

K. H. Kim ,
W. T. Elam  and
E. F. Skelton
K. H. Kim
Affiliation:
NRC/NRL Cooperative Research Associate
W. T. Elam
Affiliation:
Naval Research Laboratory, Washington, D. C., 20375
E. F. Skelton
Affiliation:
Naval Research Laboratory, Washington, D. C., 20375
Get access

Abstract

Extended x-ray absorption fine structure (EXAFS) of potassium niobate (KnbO3 ) was measured at the K edge of Nb, at various temperatures to include all phases of the material. The first shell data were analyzed to determine the distances between the niobium atom and its oxygen neighbors. The single shell amplitude almost vanishes around k-7.5 A−1 at all temperatures, suggesting two distances with a separation of about 0.21 A. Nonlinear fitting was used to determine the structure more carefully and the data at all temperatures can be fit reasonably well with two Nb-O ditances. This is in disagreement with the displacive model which implies only one Nb-O distance in the cubic phase. This result suggests that the niobium atom is displaced along the (111) direction relative to the oxygen atom in all phases. Thus, the transitions are not displacive, but have a strong order-disorder character.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 172: Symposium P – Optical Fiber Materials and Processing , 1989 , 291
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1 Lines, M. E. and Glass, A. M., Principles and Apvlications of Ferroelectrics and Related Materials, (Clarendon Press, Oxford, 1977) and references thereinGoogle Scholar
2 Hewat, A. W., J. Phys. C6, 2559 (1973)Google Scholar
3 Comes, R., Lambert, M. and Guinier, A., Acta Cryst., A26, 244 (1970)Google Scholar
4 Chase, L. L., Sokoloff, J. and Boatner, L. A., Solid State Comm. 55, 451 (1985)Google Scholar
5 Sokoloff, J. P., Chase, L. L. and Rytz, D., Phys. Rev. B38, 597 (1988)Google Scholar
6 Fontana, M. D., Metrat, G., Servoin, J. L. and Gervais, F., J. Phys. C17, 483 (1984)Google Scholar
7 Gervais, F., Ferroelectrics 53, 91 (1984)Google Scholar
8 Hanskepetitpierre, O., Stern, E. A. and Yacoby, Y., J. de Physique C8, 675 (1986)Google Scholar
9 Kim, K., Ph. D. dissertation, University of Washington, 1985 (unpublished)Google Scholar
10 Sayers, D. E. and Bunker, B. A., in X-ray Absorption, edited by Koningsberger, D. C. and Prins, R. (Wiley, New York, 1988), p. 211 Google Scholar
11 Muller, J. E. and Schaich, W. L., Phys. Rev. B27, 6489 (1983)Google Scholar
12 Edwardson, P. J., Phys. Rev. Lett. 63, 55 (1989)Google Scholar