New stable decagonal quasicrystal in the system Al–Ir–Os

Katrych, S.; Weber, Th.; Kobas, M.; Massüger, Lars; Palatinus, Lukáš; Chapuis, G.; Steurer, Walter

doi:10.1016/j.jallcom.2006.03.064

Cited by 40 publications

(28 citation statements)

References 21 publications

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“…Its bulk composition is 57 at% Al, 30 at% Pd and 13 at% Zn. It is structurally similar to a known Al-Os-Ir phase [14]. It melts congruently at 1045 K. The synthesis and analysis of this material will be reported elsewhere [10].…”

Section: Introductionmentioning

confidence: 89%

Weak bonding of Zn in an Al-based approximant based on surface measurements

Yuen

Ünal

Jing

et al. 2010

Philosophical Magazine

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We have studied two surfaces of a new Al-Pd-Zn approximant using mass spectrometry, X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). Zn is bonded weakly in this approximant, perhaps as weakly as in elemental Zn. This is based upon three observations: (1) the low vapor pressure of Zn above the approximant (detectable in the gas phase at 600 K), (2) preferential sputtering of Zn (contrary to the usual preferential sputtering of Al in Al-rich quasicrystals), and (3) preferential surface segregation of Zn. We further show that preferential segregation -and perhaps incipient evaporation -causes the surface to roughen, preventing it from forming a terrace-step morphology. Finally, our data show that at low O2 pressures, Al oxidizes. In air, Zn oxidizes as well. All results and conclusions are similar for the two-fold and pseudo-10-fold surfaces. RightsThis article is (co-)authored by an employee of the United States Government and is not subject to copyright in the United States (17 U.S.C. §105). Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden.The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material. We have studied two surfaces of a new Al-Pd-Zn approximant using mass spectrometry, X-ray photoemission spectroscopy (XPS) and scanning tunneling microscopy (STM). Zn is bonded weakly in this approximant, perhaps as weakly as in elemental Zn. This is based upon three observations: (1) the low vapor pressure of Zn above the approximant (detectable in the gas phase at 600 K), (2) preferential sputtering of Zn (contrary to the usual preferential sputtering of Al in Al-rich quasicrystals), and (3) preferential surface segregation of Zn. We further show that preferential segregation -and perhaps incipient evaporation -causes the surface to roughen, preventing it from forming a terrace-step morphology. Finally, our data show that at low O 2 pressures, Al oxidizes. In air, Zn oxidizes as well. All results and conclusions are similar for the two-fold and pseudo-10-fold surfaces. Philosophical MagazineVol. 91, Nos. 19-21, 1-21 July 2011, 2879-

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Section: Introductionmentioning

confidence: 89%

Weak bonding of Zn in an Al-based approximant based on surface measurements

Yuen

Ünal

Jing

et al. 2010

Philosophical Magazine

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“…Charge flipping is such an alternative method that can be used to solve crystal structures for up to several hundreds of atoms in the unit cell from diffraction data with atomic resolution (Oszlá nyi & Sü tö, 2004, 2005. Charge flipping has been shown to be applicable to standard crystal structures (Wu et al, 2004;Oszlá nyi et al, 2006), but it has also proved very useful in the solution of incommensurately modulated structures (Palatinus, 2004;Zuñ iga et al, 2006;, quasicrystals (Katrych et al, 2007) and structures solved from powder diffraction data (Wu et al, 2006;Baerlocher et al, 2007). From the practical point of view, the method has only one serious disadvantage, namely the requirement of a complete or almost complete data set.…”

Section: Introductionmentioning

confidence: 99%

Extending the charge-flipping method towards structure solution from incomplete data sets

2007

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The charge-flipping method tends to fail if applied to an incomplete diffraction data set. The reason is artifacts induced in the density maps by Fourier transforming the data. It is shown that the missing data can be sufficiently well approximated on the basis of the Patterson map of the unknown structure optimized by the maximum entropy method (MEM). Structures that could not be solved by the original charge-flipping algorithm can be solved by the proposed method. The method has been tested on experimental data of one inorganic and two organic structures and on several types of missing data. In many cases, up to 50% of missing reflections, or even more, can be tolerated and the structure can still be reconstructed by charge flipping.

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“…Soon, the method was successfully applied to the first unknown modulated structures (Zuniga et al, 2006;Palatinus et al, 2006). The method was also quickly applied to decagonal quasicrystals (Fleischer & Steurer, 2007;Strutz & Steurer, 2007;Katrych et al, 2007). In the latter work it was demonstrated how using only an approximant to gain insight into the true quasicrystal structure may sometimes lead to incorrect conclusions.…”

Section: Incommensurately Modulated Structures and Quasicrystalsmentioning

confidence: 99%

The charge-flipping algorithm in crystallography

Palatinus

2013

Acta Crystallogr B Struct Sci Cryst Eng Mater

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The charge-flipping algorithm (CFA) is a member of the diverse family of dual-space iterative phasing algorithms. These algorithms use alternating modifications in direct and reciprocal space to find a solution to the phase problem. The current state-of-the-art CFA is reviewed and it is put in the context of related dual-space algorithms with relevance for crystallography. The CFA has found applications in many crystallographic problems. The principal applications in various fields are described with sections devoted to routine structure solution, the solution of complex structures from powder diffraction data, the solution of incommensurately modulated crystals and quasicrystals, macromolecular crystallography and single-particle imaging.

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New stable decagonal quasicrystal in the system Al–Ir–Os

Cited by 40 publications

References 21 publications

Weak bonding of Zn in an Al-based approximant based on surface measurements

Weak bonding of Zn in an Al-based approximant based on surface measurements

Extending the charge-flipping method towards structure solution from incomplete data sets

The charge-flipping algorithm in crystallography

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