scholarly journals Long-range scans and many-beam effects for high-resolution x-ray diffraction from multilayered structures: Experiment and theory

2008 ◽  
Vol 77 (17) ◽  
Author(s):  
T. A. Alexeeva ◽  
A. I. Benediktovich ◽  
I. D. Feranchuk ◽  
T. Baumbach ◽  
A. Ulyanenkov
Keyword(s):  
High Resolution ◽  
Long Range ◽  
X Ray Diffraction ◽  
Multilayered Structures ◽  
X Ray

D-1 Invited—Long Range Scans and Many-Beam Effects for High-Resolution X-ray Diffraction From Multilayered Structures

2008 ◽  
Vol 23 (2) ◽  
pp. 174-174
Author(s):  
T. A. Ulyanenkova ◽  
T. Baumbach ◽  
A. I. Benediktovich ◽  
I. Feranchuk ◽  
A. Ulyanenkov
Keyword(s):  
High Resolution ◽  
Long Range ◽  
X Ray Diffraction ◽  
Multilayered Structures ◽  
X Ray

High-Resolution Small-Angle X-Ray Diffraction Study of Long-Range Order in Hard-Sphere Colloidal Crystals

2002 ◽  
Vol 88 (20) ◽  
Author(s):  
A. V. Petukhov ◽  
D. G. A. L. Aarts ◽  
I. P. Dolbnya ◽  
E. H. A. de Hoog ◽  
K. Kassapidou ◽  
...  
Keyword(s):  
High Resolution ◽  
Diffraction Study ◽  
Long Range ◽  
Small Angle ◽  
Hard Sphere ◽  
Colloidal Crystals ◽  
Range Order ◽  
Long Range Order ◽  
X Ray Diffraction ◽  
X Ray

Fullerene Superconductors: Effects of Molecular Orientation and Valence

1994 ◽  
Vol 359 ◽  
Author(s):  
T. Yildirim ◽  
L. Barbedette ◽  
K. KniaŹ ◽  
J. E. Fischer ◽  
C. L. Lin ◽  
...  
Keyword(s):  
High Resolution ◽  
Raman Scattering ◽  
Long Range ◽  
Molecular Orientation ◽  
Alkaline Earth ◽  
X Ray Diffraction ◽  
Cubic Symmetry ◽  
X Ray ◽  
Mixed Alkali ◽  
Theoretical Predictions

ABSTRACTWe report results of high-resolution x-ray diffraction, dc magnetometry and Raman scattering on the quaternary alkali and ternary mixed alkali-alkaline earth fullerene compounds Na2RbxCs1−x C60 (0 < x < 1) and Rb3−δ BaδC60 (δ ∼ 0.4 and 2.0). These have the same cubic space lattices as K3C60 and Rb3C60 however the former exhibit long-range orientational correlations with Pa3 symmetry and the latter have N > 3 delocalized electrons per molecule. We show that the dependence of Tc on lattice constant is much steeper for the ordered as compared to the merohedrally disordered phases with N = 3, and that within the constraint of cubic symmetry Tc decreases significantly with increasing N > 3, in disagreement with some theoretical predictions.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Tubulin structure at intermediate resolution

1995 ◽  
Vol 53 ◽  
pp. 852-853
Author(s):  
K. H. Downing ◽  
S. G. Wolf ◽  
E. Nogales
Keyword(s):  
High Resolution ◽  
Structural Data ◽  
Therapeutic Drug ◽  
Zinc Ions ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Stain ◽  
Functional Mechanisms ◽  
Tubulin Structure

Microtubules are involved in a host of critical cell activities, many of which involve transport of organelles through the cell. Different sets of microtubules appear to form during the cell cycle for different functions. Knowledge of the structure of tubulin will be necessary in order to understand the various functional mechanisms of microtubule assemble, disassembly, and interaction with other molecules, but tubulin has so far resisted crystallization for x-ray diffraction studies. Fortuitously, in the presence of zinc ions, tubulin also forms two-dimensional, crystalline sheets that are ideally suited for study by electron microscopy. We have refined procedures for forming the sheets and preparing them for EM, and have been able to obtain high-resolution structural data that sheds light on the formation and stabilization of microtubules, and even the interaction with a therapeutic drug.Tubulin sheets had been extensively studied in negative stain, demonstrating that the same protofilament structure was formed in the sheets and microtubules. For high resolution studies, we have found that the sheets embedded in either glucose or tannin diffract to around 3 Å.

scholarly journals Emergent long-range magnetic order in ultrathin (111)-oriented LaNiO3 films

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Margaret M. Kane ◽  
Arturas Vailionis ◽  
Lauren J. Riddiford ◽  
Apurva Mehta ◽  
Alpha T. N’Diaye ◽  
...  
Keyword(s):  
Long Range ◽  
Degrees Of Freedom ◽  
Magnetic Order ◽  
Magnetic Ordering ◽  
Anomalous Hall Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
Range Magnetic Order ◽  
Film Substrate ◽  
Long Range Magnetic Order

AbstractThe emergence of ferromagnetism in materials where the bulk phase does not show any magnetic order demonstrates that atomically precise films can stabilize distinct ground states and expands the phase space for the discovery of materials. Here, the emergence of long-range magnetic order is reported in ultrathin (111) LaNiO3 (LNO) films, where bulk LNO is paramagnetic, and the origins of this phase are explained. Transport and structural studies of LNO(111) films indicate that NiO6 octahedral distortions stabilize a magnetic insulating phase at the film/substrate interface and result in a thickness-dependent metal–insulator transition at t = 8 unit cells. Away from this interface, distortions relax and bulk-like conduction is regained. Synchrotron x-ray diffraction and dynamical x-ray diffraction simulations confirm a corresponding out-of-plane unit-cell expansion at the interface of all films. X-ray absorption spectroscopy reveals that distortion stabilizes an increased concentration of Ni2+ ions. Evidence of long-range magnetic order is found in anomalous Hall effect and magnetoresistance measurements, likely due to ferromagnetic superexchange interactions among Ni2+–Ni3+ ions. Together, these results indicate that long-range magnetic ordering and metallicity in LNO(111) films emerges from a balance among the spin, charge, lattice, and orbital degrees of freedom.

scholarly journals Dislocation Arrangement in a Thick LEO GaN Film on Sapphire

2000 ◽  
Vol 5 (S1) ◽  
pp. 97-103
Author(s):  
Kathleen A. Dunn ◽  
Susan E. Babcock ◽  
Donald S. Stone ◽  
Richard J. Matyi ◽  
Ling Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Electron Diffraction ◽  
Threading Dislocations ◽  
X Ray Diffraction ◽  
Burgers Vector ◽  
X Ray ◽  
The Third ◽  
Dislocation Arrangement ◽  
Image Position ◽  
Gan Film

Diffraction-contrast TEM, focused probe electron diffraction, and high-resolution X-ray diffraction were used to characterize the dislocation arrangements in a 16µm thick coalesced GaN film grown by MOVPE LEO. As is commonly observed, the threading dislocations that are duplicated from the template above the window bend toward (0001). At the coalescence plane they bend back to lie along [0001] and thread to the surface. In addition, three other sets of dislocations were observed. The first set consists of a wall of parallel dislocations lying in the coalescence plane and nearly parallel to the substrate, with Burgers vector (b) in the (0001) plane. The second set is comprised of rectangular loops with b = 1/3 [110] (perpendicular to the coalescence boundary) which originate in the coalescence boundary and extend laterally into the film on the (100). The third set of dislocations threads laterally through the film along the [100] bar axis with 1/3<110>-type Burgers vectors These sets result in a dislocation density of ∼109 cm−2. High resolution X-ray reciprocal space maps indicate wing tilt of ∼0.5º.

Investigation of Residual Strains of the Second Kind in Plastically Deformed Metallic Materials

1994 ◽  
Vol 376 ◽  
Author(s):  
M. Vrána ◽  
P. Klimanek ◽  
T. Kschidock ◽  
P. Lukáš ◽  
P. Mikula
Keyword(s):  
High Resolution ◽  
Neutron Diffraction ◽  
Stacking Faults ◽  
Metallic Materials ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutron Diffractometer ◽  
Residual Strains ◽  
Good Agreement

ABSTRACTInvestigation of strongly distorted crystal structures caused by dislocations, stacking-faults etc. in both plastically deformed f.c.c. and b.c.c. metallic materials was performed by the analysis of the neutron diffraction line broadening. Measurements were realized by means of the high resolution triple-axis neutron diffractometer equipped by bent Si perfect crystals as monochromator and analyzer at the NPI Řež. The substructure parameters obtained in this manner are in good agreement with the results of X-ray diffraction analysis.

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