Skip to content

SEARCH · Engineering Papers

Results for “MONOCRYSTALS”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,477 records · Page 82

All sources NASA NTRS DOE OSTI

DOE OSTI2013

Synthesis and crystal structure of α,β-unsaturated ketone: 3,3′-[1,2-ethanediylbis(oxy-2,1-phenylene)]bis[1-(2-pyridyl)-2-propen-1-one]

The title compound, C{sub 30}H{sub 24}N{sub 2}O{sub 4}, 3,3′-[1,2-ethanediyl-bis(oxy-2,1-phenylene)]bis[1-(2-pyridyl)-2-propen-1-one] was synthesized and characterized by elemental analysis, FT-IR spectra, {sup 1}H NMR, and X-ray single-crystal diffraction. In the molecule, the pyridine plane and the adjacent phenyl plane are almost coplanar with the dihedral angle of 3.07°, while the dihedral angle between the mean planes of the two asymmetric units is 67.56°. The crystal packing is stabilized by weak intermolecular C-H...N and C-H...O hydrogen bonds, C-H...π and π...π stacking interactions.

36 MATERIALS SCIENCE↗

DOE OSTI2015

Change in the structural imperfection of lithium niobate crystals doped with zinc

The changes in the degree of structural imperfection of lithium niobate (LiNbO{sub 3}) single crystals with an increase in the Li content and doping with zinc (to 1 wt %) have been investigated by the nonlinear optics methods and Raman spectroscopy. The conversion of broadband IR radiation in LiNbO{sub 3} crystals under noncritical (90°) phase-matching condition with vector interactions implemented is investigated. It is shown that the conversion efficiency, spectral width, and the position of maximum in the converted radiation spectrum depend on the ratio R = Li/Nb in LiNbO{sub 3} crystal and the impurity concentration.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

New scientific equipment for protein crystallization in microgravity, BELKA, and its approbation on the Bion-M No. 1 spacecraft

A space experiment on the crystallization of lisozyme and glucose isomerase proteins in UK-1 and UK-2 crystallizers on the scientific equipment BELKA on the Bion-M no. 1 spacecraft was performed in April–May 2013. A ground-based experiment was carried out simultaneously at the Institute of Crystallography of the Russian Academy of Sciences (IC RAS). Transparent crystals were obtained in both cases. The lisozyme crystals grown in microgravity are larger than their terrestrial analogs. An optical study of glucose isomerase crystals grown in space has shown that the coalescence of equally oriented crystallites leads to the formation of quasi-single-crystal blocks. An X-ray diffraction experiment on lisozyme crystals has revealed the resolutions for crystals obtained under terrestrial conditions and in space to be 1.74 and 1.58 Å, respectively.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Synthetic shibkovite K(K{sub 1.67}H{sub 2}O{sub 0.33})(Ca{sub 1.3}Na{sub 0.7})[Zn{sub 3}Si{sub 12}O{sub 30}]: the crystal structure and comparative crystal chemistry

The structure of a single crystal of a synthetic analog of mineral shibkovite K(K{sub 1.67}H{sub 2}O{sub 0.33})(Ca{sub 1.3}Na{sub 0.7})[Zn{sub 3}Si{sub 12}O{sub 30}] (milarite structure type) obtained by hydrothermal synthesis in the AlPO{sub 4}-K{sub 3}PO{sub 4}-CaCO{sub 3}-Na{sub 2}CO{sub 3}-ZnCO{sub 3}-SiO{sub 2}-H{sub 2}O system has been solved (R = 0.0406) by X-ray diffraction analysis: a = 10.5327(2) Å, c = 14.2019(3) Å, sp. gr. P6/mcc, Z = 2, and ρ{sub calcd} = 2.90 g/cm{sup 3}. The crystal-chemical features of the new phase are studied in comparison with the other terms of the milarite group. It is shown that the crystallization conditions for minerals and synthetic analogs of this group determine the presence or absence of crystallization water in the structures of compounds.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Crystal structure of a new polymorphic modification of niahite, NH{sub 4}MnPO{sub 4} · H{sub 2}O

The crystal structure of a new modification of the niahite mineral NH{sub 4}MnPO{sub 4} · H{sub 2}O, obtained in the form of single crystals under hydrothermal conditions in the Mn{sub 2}O{sub 3}-(NH{sub 4}){sub 3}PO{sub 4}-H{sub 2}O system, is determined by X-ray diffraction (Xcalibur-S-CCD diffractometer, R = 0.0259): a = 17.582, b = 4.909, and c = 5.731 Å; space group D{sub 2h}{sup 16} = Pnam, Z = 4, D{sub x} = 2.497 g/cm{sup 3}. It is shown that the new compound is a polymorphic modification of niahite; it has a layered structure, which differs from the structure of the mineral by the presence of the center of inversion and the doubled a unit cell parameter. It is proposed to consider the minerals and synthetic analogues of the niahite and triphylite groups as members of the common polysomatic series.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Single-crystal structure study of iron chalcogenides Fe{sub 1+δ}Te{sub 1−x}S{sub x}

Single crystals of iron chalcogenides Fe{sub 1+δ}Te{sub 1−x}S{sub x} (x = 0, 0.09, and 0.1) were studied by scanning, transmission, and scanning transmission electron microscopy. In addition, a sample with x = 0 was studied by X-ray diffraction. The Te-site disorder observed in Fe{sub 1+δ} samples is, apparently, assigned to the incorporation of superstoichiometric iron Fe2 into the structure. The Fe1 atoms were found to be displaced from their ideal positions, which can only partially be attributed to electro-optical effects. The replacement of Te atoms by S in Fe{sub 1+δ}Te{sub 1−x}S{sub x} crystals gives rise to domains with ordered S atoms in some regions of the single crystal, resulting in the formation of a 2 × 1 or 2 × 2 superstructure.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Iron-rich bustamite from Broken Hill, Australia: The crystal structure and cation-ordering features

A specimen of iron-rich bustamite from the Broken Hill deposit (Australia) has been studied by single-crystal X-ray diffraction and by Mössbauer and IR spectroscopy. The triclinic unit-cell parameters are as follows: a = 7.1301(4) Å, b = 7.6940(3) Å, c = 7.7345(4) Å, α = 79.352(4)°, β = 62.951(6)°, γ = 76.149(3)°, V = 365.49(3) Å{sup 3}, sp. gr. P1̄. The structure is solved by direct methods and refined to R = 5.22% based on 7298 reflections with |F| > 4σ(F). The mineral under study is similar in composition and structure to the Fe-rich bustamite described earlier. It is found that all iron atoms are in the divalent state and occupy the M1 and M3 sites in a ratio of 33: 67. The idealized formula of iron-rich bustamite from Broken Hill (Z = 1) is Mn{sub 2}Ca{sub 2}(Fe,Mn)Ca[Si{sub 3}O{sub 9}]{sub 2}.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Growth of large naphthalene and anthracene single-crystal sheets at the liquid–air interface

The growth of organic single crystals of naphthalene (C{sub 10}H{sub 8}) and anthracene (C{sub 14}H{sub 10}) at the liquid‒air interface from a mixture of solvents has been investigated. The growth technique used in the study makes it possible to obtain single-crystal sheets up to 10 mm in size for 24 h. The surface morphology and structure of the crystals have been analyzed by optical microscopy and X-ray diffraction. C{sub 10}H{sub 8} and C{sub 14}H{sub 10} single crystals grow coplanarly along the (001) plane. A thermodynamic model of the flat-crystal nucleus formation at the liquid‒air interface, based on the analysis of the change in the free Gibbs energy, is considered.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Electron microscopy of iron chalcogenide FeTe(Se) films

The structure of Fe{sub 1+δ}Te{sub 1−x}Se{sub x} films (x = 0; 0.05) grown on single-crystal MgO and LaAlO{sub 3} substrates has been investigated by transmission and scanning transmission electron microscopy. The study of Fe{sub 1.11}Te/MgO structures has revealed two crystallographic orientation relationships between the film and substrate. It is shown that the lattice mismatch between the film and substrate is compensated for by the formation of misfit dislocations. The Burgers vector projection is determined. The stresses in the film can partially be compensated for due to the formation of an intermediate disordered layer. It is shown that a FeTe{sub 0.5}Se{sub 0.5} film grown on a LaAlO{sub 3} substrate is single-crystal and that the FeTe{sub 0.5}Se{sub 0.5}/LaAlO{sub 3} interface in a selected region is coherent. The orientation relationships between the film and substrate are also determined for this case.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Growth of twin-free b-oriented YBa{sub 2}Cu{sub 3}O{sub 7} {sub −x} films

YBa{sub 2}Cu{sub 3}O{sub 7−x} films of b orientation have been grown on the surface of (100)SrLaGaO{sub 4} crystal. It is demonstrated that the films pass to the superconducting state at a temperature of 89 K. In the nonsuper-conducting region, the film resistance decreases linearly with a decrease in temperature at a rate of 30 Ω per 100°C. According to the X-ray diffraction data on the crystallographic structure of the YBa{sub 2}Cu{sub 3}O{sub 7−x} films, they are single-crystal and b-oriented. It is shown that the films contain no domains of other crystallographic orientations, including a-oriented domains. Therefore, the films are free of structural twins.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

The crystal structure and microtwinning of ferro-pedrizite, a new lithium amphibole

The structure of ferro-pedrizite—a new lithium mineral of the amphibole supergroup—has been studied by single-crystal X-ray diffraction. Fe{sup 2+} ions dominate over Mg in the chemical composition of this mineral. The parameters of the monoclinic unit cell are a = 9.3716(4) Å, b = 17.649(1) Å, c = 5.2800(6) Å, and β = 102.22(1)°. The experimental set of intensities contains a large number of significant reflections (~10%), which violate the Clattice. Consideration of pseudomerohedral twinning (matrix [1 0 0/01̄0/–3/4 01̄]) allowed us to solve and refine the structure within the sp. gr. C2/m to the final value R = 3.9% in the anisotropic approximation of atomic displacements using 4843I > 2σ(I). The twin components are found to be 0.681(3)/0.319(3). Twinning has been revealed for the first time in amphiboles of the pedrizite family. The idealized formula of ferro-pedrizite (Z = 2) is determined as NaLi{sub 2}(Fe{sub 2}{sup 2+}Al{sub 2}Li)[Si{sub 8}O{sub 22}](OH){sub 2}.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Interdomain region in single-crystal lithium niobate bimorph actuators produced by light annealing

The interdomain region of a bidomain strucrture formed in 127°-cut lithium niobate single crystals using light annealing has been studied by optical and scanning probe microscopies. A periodic subdomain structure on the 180° macrodomain wall is visualized by piezoresponse force microscopy. The piezoresponse signal (polarization) is shown to be a power-law function of the domain width with an exponent n = 0.53.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Investigation of the structure of Cs{sub 3}(HSO{sub 4}){sub 2}(H{sub 2}PO{sub 4}) single crystals

Cs{sub 3}(HSO{sub 4}){sub 2}(H{sub 2}PO{sub 4}) single crystals, obtained for the first time based on a systematic study of the phase diagram of the CsH{sub 2}PO{sub 4}–CsHSO{sub 4}–H{sub 2}O ternary system, have been studied by X-ray diffraction. The atomic structure of the crystals at room temperature is determined, and their structural features are analyzed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Orthorhombic YBaCo{sub 4}O{sub 8.4} crystals as a result of saturation of hexagonal YBaCo{sub 4}O{sub 7} crystals with oxygen

Hexagonal YBaCo{sub 4}O{sub 7} crystals (sp. gr. P6{sub 3}mc, a{sub h} = 6.3058(4) Å, c{sub h} = 10.2442(7) Å, Z = 2) are saturated with oxygen to the YBaCo{sub 4}O{sub 8.4} composition and studied by X-ray diffraction (XRD) analysis. The saturation is completed by a structural first-order phase transition to orthorhombic crystals (sp. gr. Pbc2{sub 1}, a{sub o} = 31.8419(2) Å, b{sub o} = 10.9239(5) Å, c{sub o} = 10.0960(5) Å, Z = 20). The connection of two lattices is expressed in terms of the action of matrix (500/120/001) on the hexagonal basis. Five structural fragments of the same type but with different degrees of order alternate along the long axis of the oxygen-saturated orthorhombic structure. The XRD data on single crystals differ from the results obtained by other researchers on ceramic samples; possible causes of these differences are discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Synthesis and X-ray diffraction study of Cu{sub 2}ZnSn(S{sub x}Se{sub 1-x}){sub 4} solid solutions

Quaternary compounds Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSnSe{sub 4} and solid solutions on their basis have been fabricated by one-temperature synthesis from elementary components: Cu, Zn, Sn, S, and Se. Single crystals of these compounds have been grown by the method of chemical gas-transport reactions from polycrystalline samples. The compositional dependence of the unit-cell parameters of Cu{sub 2}ZnSn(S{sub x}Se{sub 1–x}){sub 4} has been investigated by X-ray diffraction. It is found that parameters a and c linearly decrease with an increase in sulfur concentration in accordance with Vegard’s law. The temperature dependences of parameters a and thermalexpansion coefficients α{sub a} of Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSnSe{sub 4} single crystals in the range of 100–300 K are determined.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Structure of compound Pr{sub 5}Mo{sub 3}O{sub 16+δ} exhibiting mixed electronic—ionic conductivity

The structure of Pr{sub 5}Mo{sub 3}O{sub 16+δ} single crystals is studied by X-ray diffraction, EDXS microanalysis, transmission microscopy, and XANES spectroscopy. It is found that in the structure Pr and Mo cations mutually replace each other, atomic positions of oxygen are split into several additional positions, and structural voids accommodate interstitial oxygen atoms (which make the main contribution to the conductivity). The disorder of the oxygen sublattice is responsible for the continuity of the framework of the ways of migration of oxygen ions.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

X-ray diffraction study of BaTiO{sub 3} single crystals before and after fast-neutron irradiation

The neutron irradiation of ferroelectrics is efficiently used to form structural states that cannot be obtained by conventional technologies. To date, the effect of neutron irradiation on the structure and properties of BaTiO{sub 3} has been studied for only ceramic materials. We have considered the influence of fast-neutron irradiation (F = 1 × 10{sup 17} cm{sup −2}) on the structure and properties of BaTiO{sub 3} single crystals for the first time. The structural changes occurring in irradiated BaTiO{sub 3} and their correlation with the behavior of dielectric and nonlinear optical characteristics are analyzed with the aid of a specially developed method for taking into account the experimental correction to diffuse scattering. Neutron irradiation to the aforementioned dose retains the polar structure of the material and only slightly changes atomic displacements. The radiationinduced structural changes occur according to the high-temperature type to form a structure similar to the cubic modification of unirradiated BaTiO{sub 3} crystal.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2015

Synthesis, crystal structure refinement, and nonlinear-optical properties of CaB{sub 3}O{sub 5}(OH): Comparative crystal chemistry of calcium triborates

Calcium triborate CaB{sub 3}O5(OH) obtained by hydrothermal synthesis in the Ca(OH){sub 2}–H{sub 3}BO{sub 3}–Na{sub 2}CO{sub 3}–KCl system is studied by single-crystal X-ray diffraction. The parameters of the orthorhombic unit cell are as follows: a = 13.490(1), b = 6.9576(3), and c = 4.3930(2) Å; V = 412.32(3) Å{sup 3} and space group Pna2{sub 1}. The structure is refined in the anisotropic approximation of the atomic displacement parameters to R = 4.28% using 972 vertical bar F vertical bar > 4σ(F). It is confirmed that the crystal structure of Ca triborate CaB{sub 3}O{sub 5}(OH) is identical to that described earlier. The hydrogen atom is localized. An SHG signal stronger than that of the quartz standard is registered. The phase transition of calcium triborate into calciborite is found on heating. The comparative crystal-chemical analysis of a series of borates with the general chemical formula 2CaO · 3B{sub 2}O{sub 3} · nH{sub 2}O (n = 0–13) with the constant CaO: B{sub 2}O{sub 3}= 2: 3 ratio and variable content of water is performed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗