Anomalous Debye-Waller factor associated with an order-disorder transformation in an Al72Ni20Co8 decagonal quasicrystal

An order-disorder transformation in a single decagonal quasicrystal of Al72Ni20Co8 is studied in detail. In X-ray diffraction, the anomalous attenuation of intensities of Bragg reflections was found around the transformation temperature, Tc. The intensity attenuation at high temperature is explained...

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Bibliographic Details
Published in:Journal of the Physical Society of Japan 2003-08, Vol.72 (8), p.1828-1831
Main Authors: ABE, Hiroshi, SAITOH, Hiroyuki, UENO, Takashi, NAKAO, Hironori, MATSUO, Yoshie, OHSHIMA, Ken-Ichi, MATSUMOTO, Hitoshi
Format: Article
Language:English
Subjects:
Applied sciences
Condensed matter: structure, mechanical and thermal properties
Equations of state, phase equilibria, and phase transitions
Exact sciences and technology
General studies of phase transitions
Lattice dynamics
Metals. Metallurgy
Order-disorder and statistical mechanics of model systems
Order-disorder transformations
statistical mechanics of model systems
Physics
Vibrational states in disordered systems
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Summary:An order-disorder transformation in a single decagonal quasicrystal of Al72Ni20Co8 is studied in detail. In X-ray diffraction, the anomalous attenuation of intensities of Bragg reflections was found around the transformation temperature, Tc. The intensity attenuation at high temperature is explained by the anomalous Debye-Waller factor in thermal lattice dynamics. In particular, the intensity ratio above Tc and below Tc depends on |G|||2 values. In addition, the intensity ratio between room temperature and high temperature shows |G[perpendicular]|2 dependence. The results correspond to the in situ observation of a local vibrational anomaly related to an atomic flip by electron microscopy [Abe et al.: Nature 421 (2003) 347]. By X-ray diffraction, dynamic fluctuations as observed in electron microscopy are also realized even on a macroscopic scale at high temperature.
ISSN:0031-9015
1347-4073
DOI:10.1143/JPSJ.72.1828