Evidence for microcrystallites in icosahedral AlMnSi |
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| Authors: | E A Stern Y Ma |
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| Institution: | Department of Physics FM-15 , University of Washington , Seattle, Washington, 98195, U.S.A. |
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| Abstract: | Abstract An analysis of extended X-ray absorption fine structure (EXAFS) measurements at the Mn K-edge of the α-crystalline and icosahedral (i) phases of MnAlSi indicates that the icosahedral cage of Mn atoms that is part of the common structural unit in both phases retains its cubic distortion in the i-phase. Neither a quasicrystalline nor a randomly connected icosahedron (icosahedral glass) model is in agreement with this experimental result. A model that is consistent with the new EXAFS results and other properties of the i-phase of MnAlSi is one in which ～40 Å crystallites of the α-phase are oriented icosahedrally along the threefold directions of the structural unit. |
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