This title appears in the Scientific Report :
2007
Please use the identifier:
http://dx.doi.org/10.1103/PhysRevB.75.014202 in citations.
Please use the identifier: http://hdl.handle.net/2128/7747 in citations.
Orientation-dependent NMR study of the giant-unit-cell intermetallics beta-Al3Mg2, Bergman-phase Mg32(Al,Zn)49, and eta'-Al74Pd22Mn4
Orientation-dependent NMR study of the giant-unit-cell intermetallics beta-Al3Mg2, Bergman-phase Mg32(Al,Zn)49, and eta'-Al74Pd22Mn4
We present a Al-27 NMR study of three giant-unit-cell complex metallic compounds, beta-Al3Mg2, the "Bergman-phase" Mg-32(Al,Zn)(49), and xi(')-Al-Pd-Mn, which contain some hundreds up to more than a thousand atoms in the unit cell. The NMR spectra of monocrystalline samples are strong...
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Personal Name(s): | Jeglic, P. |
---|---|
Komelj, M. / Klanjsek, M. / Tkalec, U. / Vrtnik, S. / Feuerbacher, M. / Dolinsek, J. | |
Contributing Institute: |
Mikrostrukturforschung; IFF-8 |
Published in: | Physical Review B Physical review / B, 75 75 (2007 2007) 1 1, S. 014202 014202 |
Imprint: |
College Park, Md.
APS
2007
|
Physical Description: |
014202 |
DOI: |
10.1103/PhysRevB.75.014202 |
Document Type: |
Journal Article |
Research Program: |
Kondensierte Materie |
Series Title: |
Physical Review B
75 |
Subject (ZB): | |
Link: |
Get full text OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://hdl.handle.net/2128/7747 in citations.
We present a Al-27 NMR study of three giant-unit-cell complex metallic compounds, beta-Al3Mg2, the "Bergman-phase" Mg-32(Al,Zn)(49), and xi(')-Al-Pd-Mn, which contain some hundreds up to more than a thousand atoms in the unit cell. The NMR spectra of monocrystalline samples are strongly inhomogeneously broadened by the electric quadrupole interaction and the line shapes are featureless and powderlike, but still exhibit significant orientation-dependent variation of the intensity on the satellite part of the spectrum in the magnetic field. Measuring orientation-dependent satellite intensity in appropriate frequency windows yields rotation patterns that can be related to the structure and symmetry of the giant unit cells. For a theoretical reproduction of the rotation patterns, we derived a distribution of the electric-field-gradient (EFG) tensors for each of the investigated compounds from existing structural models using point-charge and ab initio calculations. The EFG distribution yields important structural information on the manifold of different local atomic environments in the unit cell and distinguishes crystallographically inequivalent lattice sites from the equivalent ones. The distribution of the EFGs for the 1168-atom unit cell of beta-Al3Mg2 was successfully determined by a point-charge calculation, whereas the ab initio approach was successful for the 160-atom unit cell of the Mg-32(Al,Zn)(49) Bergman phase. For the 258-atom unit cell of xi(')-Al-Pd-Mn, the experimental rotation patterns revealed a pseudotenfold symmetry, whereas the theoretical point-charge calculation revealed predominant twofold symmetry with traces of tenfold symmetry, so that no quantitative matching between the theory and experiment could be obtained. |