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Atomic structure solution of the complex quasicrystal approximant Al 77 Rh 15 Ru 8 from electron diffraction data
Author(s) -
Samuha Shmuel,
Mugnaioli Enrico,
Grushko Benjamin,
Kolb Ute,
Meshi Louisa
Publication year - 2014
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520614022033
Subject(s) - electron diffraction , quasicrystal , crystallography , orthorhombic crystal system , high resolution transmission electron microscopy , electron crystallography , diffraction , intermetallic , phase (matter) , reflection high energy electron diffraction , selected area diffraction , materials science , crystal structure , chemistry , physics , optics , organic chemistry , alloy , composite material
The crystal structure of the novel Al 77 Rh 15 Ru 8 phase (which is an approximant of decagonal quasicrystals) was determined using modern direct methods (MDM) applied to automated electron diffraction tomography (ADT) data. The Al 77 Rh 15 Ru 8 E‐phase is orthorhombic [ Pbma , a = 23.40 (5), b = 16.20 (4) and c = 20.00 (5) Å] and has one of the most complicated intermetallic structures solved solely by electron diffraction methods. Its structural model consists of 78 unique atomic positions in the unit cell (19 Rh/Ru and 59 Al). Precession electron diffraction (PED) patterns and high‐resolution electron microscopy (HRTEM) images were used for the validation of the proposed atomic model. The structure of the E‐phase is described using hierarchical packing of polyhedra and a single type of tiling in the form of a parallelogram. Based on this description, the structure of the E‐phase is compared with that of the ε 6 ‐phase formed in Al–Rh–Ru at close compositions.