Growth of simple icosahedral single quasicrystals in the Zn-Mg-Ho system

Uhrig, E.; Brühne, Stefan; Sterzel, R.; Schröpfer, L.; Aßmus, W.

doi:10.1080/0950083031000088104

Cited by 17 publications

(21 citation statements)

References 23 publications

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“…Mg-Zn-RE quasicrystals of comparable quality but with a P-type lattice, a(6D) ≈ 5.2 Å are also known [8]. They are called simple icosahedral (si) and are found at higher zinc-magnesium ratios for RE = Er, Ho and Tm [9,10].…”

Section: Introductionmentioning

confidence: 99%

The local atomic quasicrystal structure of the icosahedral Mg₂₅Y₁₁Zn₆₄alloy

Brühne¹,

Uhrig²,

Gross³

et al. 2005

J. Phys.: Condens. Matter

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A local and medium range atomic structure model for the face centred icosahedral (fci) Mg 25 Y 11 Zn 64 alloy has been established in a sphere of r = 27 Å. The model was refined by least squares techniques using the atomic pair distribution (PDF) function obtained from synchrotron powder diffraction. Three hierarchies of the atomic arrangement can be found: (i) five types of local coordination polyhedra for the single atoms, four of which are of FrankKasper type. In turn, they (ii) form a three-shell (Bergman) cluster containing 104 atoms, which is condensed sharing its outer shell with its neighbouring clusters and (iii) a cluster connecting scheme corresponding to a threedimensional tiling leaving space for few glue atoms. Inside adjacent clusters, Y 8 -cubes are tilted with respect to each other and thus allow for overall icosahedral symmetry. It is shown that the title compound is essentially isomorphic to its holmium analogue. Therefore fci-Mg-Y-Zn can be seen as the representative structure type for the other rare earth analogues fci-Mg-Zn-RE (RE = Dy, Er, Ho, Tb) reported in the literature.

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Section: Introductionmentioning

confidence: 99%

The local atomic quasicrystal structure of the icosahedral Mg₂₅Y₁₁Zn₆₄alloy

Brühne¹,

Uhrig²,

Gross³

et al. 2005

J. Phys.: Condens. Matter

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“…The si-Zn 74 Mg 15 Ho 11 single-grain quasicrystals were grown by the liquid-encapsulated top-seeded solutiongrowth method [3]. The structural perfection of the quasicrystals was confirmed by the sharp, resolution limited, Bragg peaks of their diffraction patterns.…”

Section: Methodsmentioning

confidence: 99%

“…The radius of the si-ZnMgHo free-electron Fermi sphere k F ¼ ð3p 2 nÞ 1=3 ¼ 1:51 Â 10 8 cm À1 lies in a close proximity to the 222100 and 311111 Bragg planes, the corresponding reciprocal lattice vectors of which, as determined from the X-ray powder diffraction pattern [3] . The analysis of the si-ZnMgHo valence band photoemission spectra [2] shows that the Fermi level is above the D 222100 pseudogap and lies within the D 311111 pseudogap.…”

Section: Modelling Of Si-znmgho Optical Responsementioning

confidence: 99%

Optical response of si-ZnMgHo quasicrystal

Karpus¹,

Babonas²,

Rėza³

et al. 2009

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract. The results of room-temperature optical study of single-grain simple icosahedral ZnMgHo quasicrystals are presented. The dielectric function eðwÞ of the quasicrystals was measured by spectroscopic ellipsometry technique in the spectral range of 0:1À7 eV. The si-ZnMgHo optical response is a superposition of the free-electron Drude-type contribution and that of the interband transitions. The experimental eðwÞ spectra are well simulated within a framework of the 'band structure hypothesis'. The deduced parameters of the si-ZnMgHo electron energy spectrum are close to their values determined previously in an analysis of the si-ZnMgHo photoemission data.

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“…In the ternary Ho-Mg-Zn system we have found another i phase, more rich in Zn, but with a simple icosahedral (si) 6D lattice: si-Ho 11 Mg 15 Zn 74 , a(6D) = 5.143(2)Å [15]. "Simple" denotes the crystallographically primitive 6D Bravais type.…”

Section: Introductionmentioning

confidence: 99%

“…Based on our results in [15], the LETSSG method [29] was used to grow large single crystals of the title compound ( Figure 1): 100 g of the pure elements zinc (99.9999%), magnesium (99.99%) and holmium (99.9%) were placed into an aluminia crucible in a ratio Zn 62.8 Mg 33.6 Ho 3.6 . 20g of an eutectic LiCl/KCl mixture is added to form an encapsulation of the melt when heated.…”

Section: Synthesismentioning

confidence: 99%

Local 3D real space atomic structure of the simple icosahedral Ho₁₁Mg₁₅Zn₇₄ quasicrystal from PDF data

Brühne¹,

Uhrig²,

Gross³

et al. 2003

Cryst. Res. Technol.

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Key words Ho-Mg-Zn simple icosahedral quasicrystals, structure analysis, atomic pair distribution function (PDF). PACS 61.44.Br, 61.10.NzWe present a new complementary strategy to quasicrystalline structure determination: The local atomic structure of simple icosahedral (si) Ho 11 Mg 15 Zn 74 [a(6D) = 5.144(3)Å] in a sphere of up to r = 17Å was refined using the atomic pair distribution function (PDF) from in-house X-ray powder diffraction data (MoKα 1 , Q max = 13.5Å -1 ; R = 20.4%). The basic building block is a 105-atom Bergman-Cluster {Ho 8 Mg 12 Zn 85 }. Its center is occupied by a Zn atom -in contrast to a void in face centred icosahedral (fci) Ho 9 Mg 26 Zn 65 . The center is then surrounded by another 12 Zn atoms, forming an icosahedron (1st shell). The 2nd shell is made up of 8 Ho atoms arranged on the vertices of a cube which in turn is completed to a pentagon dodecahedron by 12 Mg atoms, the dodecahedron then being capped by 12 Zn atoms. The 3rd shell is a distorted soccer ball of 60 Zn atoms, reflecting the higher Zn content of the si phase compared to the fci phase. In our model, 7% of all atoms are situated in between the clusters. The model corresponds to a hypothetical 1/1-approximant of the icosahedral (i) phase. The local coordinations of the single atoms are of a much distorted FrankKasper type and call to mind those present in 0/1-Mg 2 Zn 11 .

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Growth of simple icosahedral single quasicrystals in the Zn-Mg-Ho system

Cited by 17 publications

References 23 publications

The local atomic quasicrystal structure of the icosahedral Mg₂₅Y₁₁Zn₆₄alloy

The local atomic quasicrystal structure of the icosahedral Mg₂₅Y₁₁Zn₆₄alloy

Optical response of si-ZnMgHo quasicrystal

Local 3D real space atomic structure of the simple icosahedral Ho₁₁Mg₁₅Zn₇₄ quasicrystal from PDF data

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Growth of simple icosahedral single quasicrystals in the Zn-Mg-Ho system

Cited by 17 publications

References 23 publications

The local atomic quasicrystal structure of the icosahedral Mg25Y11Zn64alloy

The local atomic quasicrystal structure of the icosahedral Mg25Y11Zn64alloy

Optical response of si-ZnMgHo quasicrystal

Local 3D real space atomic structure of the simple icosahedral Ho11Mg15Zn74 quasicrystal from PDF data

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The local atomic quasicrystal structure of the icosahedral Mg₂₅Y₁₁Zn₆₄alloy

The local atomic quasicrystal structure of the icosahedral Mg₂₅Y₁₁Zn₆₄alloy

Local 3D real space atomic structure of the simple icosahedral Ho₁₁Mg₁₅Zn₇₄ quasicrystal from PDF data