Effect of Pressure on Valence and Structural Properties of YbFe2Ge2Heavy Fermion Compound—A Combined Inelastic X-ray Spectroscopy, X-ray Diffraction, and Theoretical Investigation

A series of niobium-containing mesoporous materials Nb-SBA-15 have been prepared by sonication–impregnation and hydrothermal process. The dispersion and structural properties of niobium-containing species were systematically characterized by X-ray diffraction, scanning...

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Structural properties of the guest species in diacyl peroxide/urea inclusion compounds: an X-ray diffraction investigation

Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences ◽

10.1098/rspa.1990.0129 ◽

1990 ◽

Vol 431 (1882) ◽

pp. 245-269 ◽

Cited By ~ 31

Keyword(s):

Single Crystal ◽

Structural Properties ◽

Inclusion Compounds ◽

X Ray Diffraction ◽

Channel Axis ◽

Guest Molecules ◽

X Ray ◽

Urea Inclusion Compounds ◽

Diacyl Peroxide ◽

Urea Inclusion

In this paper we report single crystal X-ray diffraction studies of urea inclusion compounds containing diacyl peroxides (dioctanoyl peroxide (OP), diundecanoyl peroxide (UP), lauroyl peroxide (LP)) as the guest component. In these inclusion compounds, the host (urea) molecules crystallize in a hexagonal structure that contains linear, parallel, non-intersecting channels (tunnels). The guest (diacyl peroxide) molecules are closely packed inside these channels with a periodic repeat distance that is incommensurate with the period of the host structure along the channel axis. Furthermore, there is pronounced inhomogeneity within the guest structure: within each single crystal, there are regions in which the guest molecules are three-dimensionally ordered, and other regions in which they are only one-dimensionally ordered (along the channel axis). Although it has not proven possible to ‘determine’ the guest structures in the conventional sense, substantial information concerning their average periodicities and their orientational relationships with respect to the host has been deduced from single crystal X-ray diffraction photographs recorded at room temperature. For OP/urea, UP/urea and LP/urea, the guest structure in the three-dimensionally ordered regions is monoclinic, and six types of domain of this monoclinic structure can be identified within each single crystal. The relative packing of diacyl peroxide molecules is the same in each domain, and the different domains are related by 60° rotation about the channel axis. For each of these inclusion compounds, the offset between the ‘heights’ of the guest molecules in adjacent channels is the same ( ca . 4.6 Å (4.6 x 10 -10 m)) within experimental error, suggesting that the relative interchannel packing of the guest molecules is controlled by a property of the diacyl peroxide group. In addition to revealing these novel structural properties, the work discussed in this paper has more general relevance concerning the measurement and interpretation of single crystal X-ray diffraction patterns that are based on more than one three-dimensionally periodic reciprocal lattice. Seven separate reciprocal lattices are required to rationalize the complete X-ray diffraction pattern from each diacyl peroxide/urea crystal studied here.

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Mechanical and Structural Properties of Superhard TiAlSiN Coatings Deposited by Arc Ion Plating of Cylindrical Cathode

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.1426 ◽

2014 ◽

Vol 783-786 ◽

pp. 1426-1431

Author(s):

Wang Ryeol Kim ◽

Min Chul Kwon ◽

Jung Hoon Lee ◽

Uoo Chang Jung ◽

Won Sub Chung

Keyword(s):

Structural Properties ◽

Nitrogen Pressure ◽

Structural Features ◽

X Ray Diffraction ◽

X Ray ◽

Ion Plating ◽

Arc Current ◽

Cathode Arc ◽

Cathodic Arc ◽

Tialsin Coating

TiAlSiN coatings were deposited on WC-Co metal by using a cathodic arc ion deposition method of cylindrical cathode. We used Ti / Al (50 / 50 at.%) arc target and silicon sputter target. The influence of the nitrogen pressure, TiAl cathode arc current, bias voltage, and deposition temperature on the mechanical and the structural properties of the films were investigated. The structural features of the films were investigation in detail using X-ray diffraction. And coatings were characterized by means of FE-SEM, nanoindentation, Scratch tester, Tribology tester, XRD and XPS. The hardness of the film reached 43 GPa at the cathode arc current of 230 A and decreased with a further increase of the arc current. And the adhesion of the film reached 34 N. The results showed that the TiAlSiN coating exhibited an excellent mechanical properties which application for tools and molds.

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Investigations of Actinide Metals and Compounds under Pressure Provide Important Insights into Bonding and Chemistry

MRS Proceedings ◽

10.1557/proc-802-dd1.5 ◽

2003 ◽

Vol 802 ◽

Cited By ~ 3

Author(s):

R. G. Haire ◽

S. Heathman ◽

T. Le Bihan ◽

A. Lindbaum ◽

M. Iridi

Keyword(s):

Structural Changes ◽

Chemical Properties ◽

X Ray Diffraction ◽

Interatomic Distances ◽

X Ray ◽

Effect Of Pressure ◽

Electronic Configurations ◽

5F Electrons ◽

Actinide Series ◽

Alloys And Compounds

ABSTRACTOne effect of pressure on elements and compounds is to decease their interatomic distances, which can bring about dramatic perturbations in their electronic nature and bonding, which can be reflected in changes in physical and/or chemical properties. One important issue in the actinide series of elements is the effect of pressure on the 5f-electrons. We have probed changes in electronic behavior with pressure by monitoring structure by X-ray diffraction, and have studied several actinide metals and compounds from thorium through einsteinium. These studies have employed angle dispersive diffraction using synchrotron radiation, and energy dispersive techniques via conventional X-ray sources. The 5f-electrons of actinide metals and their alloys are often affected significantly by pressure, while with compounds, the structural changes are often not linked to the involvement of 5 f-electron. We shall present some of our more recent findings from studies of selected actinide metals, alloys and compounds under pressure. A discussion of the results in terms of the changes in electronic configurations and bonding with regard to the element's position in the series is also addressed.

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Crystallization of Zn-rich and P-rich amorphous Zn3P2 thin films

Canadian Journal of Physics ◽

10.1139/p88-060 ◽

1988 ◽

Vol 66 (5) ◽

pp. 373-375 ◽

Cited By ~ 4

Author(s):

C. J. Arsenault ◽

D. E. Brodie

Keyword(s):

Thin Film ◽

Thin Films ◽

Activation Energy ◽

Electrical Properties ◽

Structural Properties ◽

Crystallization Process ◽

X Ray Diffraction ◽

Electrical Measurements ◽

Conductivity Activation Energy ◽

X Ray

Zn-rich and P-rich amorphous Zn3P2 thin films were prepared by co-evaporation of the excess element during the normal Zn3P2 deposition. X-ray diffraction techniques were used to investigate the structural properties and the crystallization process. Agglomeration of the excess element within the as-made amorphous Zn3P2 thin film accounted for the structural properties observed after annealing the sample. Electrical measurements showed that excess Zn reduces the conductivity activation energy and increases the conductivity, while excess P up to 15 at.% does not alter the electrical properties significantly.

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Synchrotron x‐ray diffraction studies of the structural properties of electrode materials in operating battery cells

Applied Physics Letters ◽

10.1063/1.117369 ◽

1996 ◽

Vol 69 (2) ◽

pp. 194-196 ◽

Cited By ~ 25

Author(s):

T. R. Thurston ◽

N. M. Jisrawi ◽

S. Mukerjee ◽

X. Q. Yang ◽

J. McBreen ◽

...

Keyword(s):

Structural Properties ◽

Electrode Materials ◽

X Ray Diffraction ◽

X Ray ◽

Battery Cells

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Magnetic Anisotropy in Electrodeposited CO Films and spin-valves on Gaas Substrates

MRS Proceedings ◽

10.1557/proc-562-21 ◽

1999 ◽

Vol 562 ◽

Cited By ~ 2

Author(s):

K. Attenborough ◽

M. Cerisier ◽

H. Boeve ◽

J. De Boeck ◽

G. Borghs ◽

...

Keyword(s):

Magnetic Anisotropy ◽

Buffer Layer ◽

Structural Properties ◽

Easy Axis ◽

Spin Valve ◽

X Ray Diffraction ◽

X Ray ◽

Cu Films ◽

Gaas Substrates ◽

Unique Spin

ABSTRACTWe have studied the magnetic and structural properties of thin electrodeposited Co and Cu layers grown directly onto (100) n-GaAs and have investigated the influence of a buffer layer. A dominant fourfold anisotropy with a uniaxial contribution is observed in 10 nm Co electrodeposited films on GaAs. An easy axis is observed in the [001] GaAs direction with two hard axes of differing coercivities parallel to the [011] and [011] directions. For thicker films the easy axes in the [001] direction becomes less pronounced and the fourfold anisotropy becomes less dominant. Co films of similar thicknesses deposited onto an electrodeposited Cu buffer layer were nearly isotropic. From X-ray diffraction 21 nm Co layers on GaAs were found to be hcp with the c-axis tending to be in the plane of the film. The anisotropy is ascribed to the Co/GaAs interface and is held responsible for the unique spin-valve properties seen recently in electrodeposited Co/Cu films.

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Effect of pressure on a mixed valence FeiiFeiii2complex

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s2053273314090986 ◽

2014 ◽

Vol 70 (a1) ◽

pp. C901-C901

Author(s):

Solveig Madsen ◽

Jacob Overgaard ◽

Bo Iversen

Keyword(s):

Phase Transition ◽

Hydrogen Bond ◽

Mixed Valence ◽

Hydrogen Bond Network ◽

X Ray Diffraction ◽

X Ray ◽

Effect Of Pressure ◽

Bond Network ◽

Fe Sites ◽

Cyano Groups

Intramolecular electron transfer (ET) in mixed valence (MV) oxo-centered [FeiiFeiii2O(carboxylate)6(ligand)3]·solvent complexes is highly dependent on temperature, on the nature of the ligands, and on the presence of crystal solvent molecules [1]. Whereas the effects of temperature, crystal solvent, and ligand variation on the details of the ET have been explored thoroughly, the effect of pressure is less well described [2]. The effect of pressure on the ET in MV Fe3O(cyanoacetate)6(water)3has been investigated with single crystal X-ray diffraction and Mössbauer spectroscopy. Previous multi-temperature studies have shown that at room temperature the ET between the three Fe sites is fast and the observed structure of the Fe3core is a perfectly equilateral triangle [3]. Cooling the complex below 130 K induces a phase transition as the ET slows down. Below 120 K the Fe3core is distorted due to the localization of the itinerant electron on one of the three Fe sites in the triangle (the complex is then in the valence trapped state). The valence trapping is complete within a temperature interval of just 10 K. The abruptness of the transition has been attributed to the extended hydrogen bond network involving water ligands and cyano groups, promoting intermolecular cooperative effects. The high-pressure X-ray diffraction data show that there is a 900flip of half the cyano groups at 3.5 GPa, which dramatically changes the hydrogen bond network. At a slightly higher pressure, a phase transition is found to occur. The five single crystals investigated all broke into minor fragments at the transition; however triclinic unit cells, similar to the low temperature unit cell, could be indexed from selected spots. Additional evidence that the complex is valence trapped comes from high pressure Mössbauer spectra measured above the phase transition (4 GPa). The relationship between valence trapping and the structural changes will in this work be highlighted using void space and Hirshfeld surface analysis.

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The Adsorption and Chemistry of Tripropyl phosphate (TPP) into Microporous and Mesoporous NaX Zeolites

MRS Proceedings ◽

10.1557/opl.2011.431 ◽

2011 ◽

Vol 1304 ◽

Author(s):

Qingguo Meng ◽

David C. Doetschman ◽

Apostolos K. Rizos ◽

Min-Hong Lee ◽

Jürgen T. Schulte ◽

...

Keyword(s):

Solid State ◽

Structural Properties ◽

Nmr Spectra ◽

Nitrogen Adsorption ◽

X Ray Diffraction ◽

X Ray ◽

Nax Zeolite ◽

Stoichiometric Amount ◽

Polydiallyldimethylammonium Chloride ◽

Adsorption Analysis

ABSTRACTAdsorption and chemistry of tripropylphosphate (TPP) in mesoporous NaX zeolite, which was templated by cationic templated polymer (polydiallyldimethylammonium chloride, PDADMAC) with two different length chains, was investigated. The structural properties of the zeolites were characterized by X-ray diffraction (XRD) and nitrogen adsorption analysis. The chemical activities of different zeolites toward the decomposition of TPP were determined with solid state 31P NMR spectra. After exposure of zeolites to TPP was sufficient and equilibrium was reached, a stoichiometric amount of water was also adsorbed and hydrolysis was observed. The TPP decomposition yields in different NaX zeolites were compared.

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Optical and Structural Properties of α-Si1-xCx Films

MRS Proceedings ◽

10.1557/proc-423-753 ◽

1996 ◽

Vol 423 ◽

Cited By ~ 1

Author(s):

Zhizhong Chen ◽

Kai Yang ◽

Rong Zhang ◽

Hongtao Shi ◽

Youdou Zheng

Keyword(s):

Structural Properties ◽

Radial Distribution ◽

Optical Constants ◽

State Density ◽

Distribution Functions ◽

X Ray Diffraction ◽

Energy Band Gap ◽

X Ray ◽

Optical Energy Band Gap ◽

Atomic Radial Distribution

AbstractIn this paper, we reported experimental results about optical and structural properties of amorphous silicon carbide (α-Si1-xCx). The films of a-Si1-xCx) were grown by CVD on substrate of quartz glass. Optical constants (n-refractive index, a-absorption coefficient, Eg-optical energy band gap) of these films were determined by transmission spectra. The radial distribution functions (RDFs) of α- Sil−xCx) films were drawn out from the data of x-ray diffraction spectra. According to the RDFs, we imagined the statistic scene from which we could obtain the information of atomic radial distribution. The bond lengths and bond numbers of Si-Si, Si-C, and C-C could be also determined by RDFs. From the analysis of Raman spectra, we obtained the information of their vibration state density, and discerned the peaks of bond vibration, which agreed well with the results of α-Si1-xCx) RDF.

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