X-ray diffraction studies of the AlPdMn quasicrystal
Abstract
The purpose of this research was to study various properties of the $\rm Al\sb{70}Pd\sb{21.5}Mn\sb{8.5}$ icosahedral quasicrystal by means of X-ray diffraction. Structure factors were measured in Bragg geometry on an absolute basis. The experimental values were compared with theoretical values and good agreement was found for weak reflections. X-ray standing wave experiments were done in back reflection mode. Different coherent positions for Al and Pd atoms were observed along the two-fold axis q$\sb{\rm z}$. Anomalous transmission was observed and the integrated reflections were measured on an absolute basis. A dynamical three-beam X-ray diffraction experiment was done using elliptically polarized X-rays. The notion that the AlPdMn icosahedral quasicrystal is non-centrosymmetric was reinforced. The temperature dependence of the intensity of Bragg reflections was investigated and the measured Debye temperature $\Theta\sb{\rm M}$ was 304 K. X-ray diffuse scattering was investigated and several unexplained diffraction peaks were characterized.
Degree
Ph.D.
Advisors
Colella, Purdue University.
Subject Area
Condensation
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