DOI: 10.1209/epl/i2001-00317-0


Europhys. Lett., 54 (6) , pp. 753-759 (2001)

Coherent -ray diffraction and phason fluctuations in quasicrystals

A. Létoublon¹, F. Yakhou², F. Livet¹, F. Bley¹, M. de Boissieu¹, L. Mancini³, R. Caudron⁴, C. Vettier⁵ and J. Gastaldi<sup>6

1</sup>  LTPCM, INPG, UMR CNRS 5614 - BP 75, 38402 St. Martin d'Heres Cedex, France
²  ESRF - BP 220, 38043 Grenoble Cedex, France
³  LAMEL-CNR - Via P. Gobetti 101, 40129 Bologna, Italy
⁴  Laboratoire d'étude des Microstructures, ONERA-CNRS - BP 72, 92320 Chatillon France and LLB, CEA, CNRS, CE Saclay - 91190 Gif-sur-Yvette, France
⁵  ILL - BP 156, 38042 Grenoble Cedex 9, France
⁶  CRMC2, CNRS, Campus de Luminy - case 913, 132888 Marseille Cedex 9, France

(Received 17 April 2000; accepted in final form 5 April 2001)

Abstract
Frozen-in phason fluctuations in single grains of icosahedral -- quasicrystals have been studied by high-resolution coherent X-ray scattering. Bragg peak widths scale as expected for a distribution of uniform phason strains. Strong relaxation of the uniform phason strain is observed after sample annealing. Large intensity fluctuations or speckle patterns are observed in the Bragg peaks due to the uniform phason strain distribution in the sample. Speckle patterns are also observed in the diffuse scattering located close to the Bragg reflections and are related to long-wavelength phason fluctuations taking place in the sample.

PACS
61.44.Br - Quasicrystals.
61.10.Eq - X-ray scattering (including small-angle scattering).


© EDP Sciences 2001