Dynamics of phason fluctuations in the i-AlPdMn quasicrystal.
We report on the study of the dynamics of long wavelength phason fluctuations in the i-AlPdMn icosahedral phase using coherent x-ray scattering. When measured with a coherent x-ray beam, the diffuse intensity due to phasons presents strong fluctuations or speckles pattern. From room temperature to 500 degrees C the speckle pattern is time independent. At 650 degrees C the time correlation of the speckle pattern exhibits an exponential time decay, from which a characteristic time tau is extracted. We find that tau is proportional to the square of the phason wavelength, which demonstrates that phasons are collective diffusive modes in quasicrystals, in agreement with theoretical predictions.
Francoual
S
S
Laboratoire de Thermodynamique et de Physico-Chimie Métallurgique, UMR CNRS 5614, ENSEEG-INPG, BP 75, 38402 Saint Martin d'Hères Cedex, France.
Livet
F
F
de Boissieu
M
M
Yakhou
F
F
Bley
F
F
Létoublon
A
A
Caudron
R
R
Gastaldi
J
J