In Situ Synchrotron Measurements of Oxide Growth Strains

2005 ◽  
Vol 490-491 ◽  
pp. 287-293 ◽  
Author(s):  
Jonathan Almer ◽  
Geoffrey A. Swift ◽  
John A. Nychka ◽  
Ersan Üstündag ◽  
David R. Clarke
Keyword(s):  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
High Energy ◽  
Oxide Growth ◽  
X Rays ◽  
Pure Alumina ◽  
Transmission Geometry ◽  
Residual Strains

Synchrotron x-rays are used for in situ determination of oxide strain, during oxide formation on a Kanthal A1 FeCrAlZr substrate at 1160°C. The measurements rely on use of high-energy (~80keV) x-rays and transmission geometry, and the methodology of the strain measurements is presented. Oxide growth strains at elevated temperature, relative to pure alumina, were seen to be small, while temperature excursions induced significant strains. Furthermore, significant strain relaxation was observed during isothermal holds, suggesting oxide creep as a major relaxation mechanism. Upon cooling to room temperature, significant residual strains developed, with a corresponding in-plane residual stress of -3.7 GPa.

scholarly journals In Situ Studies of Light Metals with Synchrotron Radiation and Neutrons

2011 ◽  
Vol 690 ◽  
pp. 192-197
Author(s):  
Peter Staron ◽  
Felix Beckmann ◽  
Thomas Lippmann ◽  
Andreas Stark ◽  
Michael Oehring ◽  
...  
Keyword(s):  
High Energy ◽  
High Time Resolution ◽  
Material Research ◽  
Light Metals ◽  
X Rays ◽  
Friction Stir ◽  
Wide Range ◽  
In Situ Experiments

High-energy X-rays and neutrons offer the large penetration depths that are often required for the determination of bulk properties in engineering material research. In addition, new sources provide very high intensities on the sample, which can be used not only for high spatial resolution using very small beams, but also for high time resolution in combination with a fast detector. This opens up possibilities for a wide range of specific engineering in situ experiments. Typical examples that are already widely used are heating or tensile testing in the beam. However, there are also more challenging experiments in the field of light metals, like e.g. friction stir welding, dilatometry, solidification, or cutting. Selected examples are presented.

scholarly journals Evidence of 2D-3D transition during the first stages of GaN growth on AlN

1997 ◽  
Vol 2 ◽  
Author(s):  
F. Widmann ◽  
B. Daudin ◽  
G. Feuillet ◽  
Y. Samson ◽  
M. Arlery ◽  
...  
Keyword(s):  
Smooth Surface ◽  
Molecular Beam ◽  
Growth Parameters ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
High Energy ◽  
Rheed Pattern ◽  
High Energy Electron ◽  
Island Coalescence

In order to identify the strain relaxation mechanism, Molecular Beam Epitaxy of wurtzite GaN on AlN was monitored in situ using Reflection High Energy Electron Diffraction (RHEED). In the substrate temperature range between 620°C and 720°C, a Stransky-Krastanov (SK) transition was evidenced, resulting in a 2D-3D transition after completion of 2 monolayers, with subsequent coalescence of 3D islands, eventually resulting in a smooth surface. Quantitative analysis of the RHEED pattern allowed us to determine that island formation is associated with elastic relaxation. After island coalescence, a progressive plastic relaxation is observed. The size and density of 3D islands was varied as a function of the growth parameters. AFM experiments revealed that the size of the GaN islands, about 8 nm large and 2 nm high, was small enough to expect quantum effects. It was found that capping of the islands by AlN resulted in a smooth surface after deposition of a few monolayers allowing us to grow a »superlattice» of islands by periodically repeating the process.

scholarly journals The X-ray stellar population of the LMC

2008 ◽  
Vol 4 (S256) ◽  
pp. 20-29 ◽  
Author(s):  
Yaël Nazé
Keyword(s):  
Stellar Population ◽  
Main Sequence ◽  
Massive Stars ◽  
High Energy ◽  
Magellanic Clouds ◽  
X Rays ◽  
X Ray ◽  
Energy Domain ◽  
X Ray Binaries

AbstractIn the study of stars, the high energy domain occupies a place of choice, since it is the only one able to directly probe the most violent phenomena: indeed, young pre-main sequence objects, hot massive stars, or X-ray binaries are best revealed in X-rays. However, previously available X-ray observatories often provided only crude information on individual objects in the Magellanic Clouds. The advent of the highly efficient X-ray facilities XMM-Newton and Chandra has now dramatically increased the sensitivity and the spatial resolution available to X-ray astronomers, thus enabling a fairly easy determination of the properties of individual sources in the LMC.

In situ time-resolved X-ray diffraction of tobermorite formation process under hydrothermal condition: Influence of reactive al compound

2011 ◽  
Vol 26 (2) ◽  
pp. 134-137 ◽  
Author(s):  
K. Matsui ◽  
A. Ogawa ◽  
J. Kikuma ◽  
M. Tsunashima ◽  
T. Ishikawa ◽  
...  
Keyword(s):  
Hydrothermal Reaction ◽  
High Energy ◽  
Saturated Steam ◽  
Array Detector ◽  
Time Interval ◽  
X Rays ◽  
X Ray Diffraction ◽  
Formation Reaction ◽  
X Ray

Hydrothermal formation reaction of tobermorite in the autoclaved aerated concrete (AAC) process has been investigated by in situ X-ray diffraction. High-energy X-rays from a synchrotron radiation source in combination with a newly developed autoclave cell and a photon-counting pixel array detector were used. XRD measurements were conducted in a temperature range 100–190°C throughout 12 h of reaction time with a time interval of 4.25 min under a saturated steam pressure. To clarify the tobermorite formation mechanism in the AAC process, the effect of Al addition on the tobermorite formation reaction was studied. As intermediate phases, non-crystalline calcium silicate hydrate (C-S-H), hydroxylellestadite (HE), and katoite (KA) were clearly observed. Consequently, it was confirmed that there were two reaction pathways via C-S-H and KA in the tobermorite formation reaction of Al containing system. In addition, detailed information on the structural changes during the hydrothermal reaction was obtained.

scholarly journals A zone melting device for the in situ observation of directional solidification using high-energy synchrotron x rays

2020 ◽  
Vol 91 (9) ◽  
pp. 093901
Author(s):  
C. Gombola ◽  
G. Hasemann ◽  
A. Kauffmann ◽  
I. Sprenger ◽  
S. Laube ◽  
...  
Keyword(s):  
Directional Solidification ◽  
High Energy ◽  
Zone Melting ◽  
In Situ Observation ◽  
X Rays

A Model for Lattice-Mismatched Epitaxy: A Continuum View

1992 ◽  
Vol 280 ◽  
Author(s):  
B. G. Orr ◽  
C. W. Snyder
Keyword(s):  
Surface Diffusion ◽  
Strain Relaxation ◽  
Relaxation Mechanism ◽  
High Energy ◽  
Growth Mode ◽  
Scanning Tunneling ◽  
Physical Factors ◽  
Diffusion Kinetics ◽  
Tunneling Microscopy ◽  
Lattice Mismatched Epitaxy

To date, primarily only idealized equilibrium models for the growth mode and strain relaxation of elastically strained overlayers have been proposed. Here we present a general continuum model for lattice-mismatched epitaxy. As molecular beam epitaxy is inherently a nonequilibrium growth process, surface diffusion kinetics is incorporated in the model. Additionally, a new strain relaxation mechanism in a dislocation-free film is considered. Experimental support for our view is obtained from measurements made by reflection high energy electron diffraction, scanning tunneling microscopy, and transmission electron microscopy on the growth of InGaAs on GaAs(100). These results demonstrate the strong effects which strain, surface diffusion kinetics, and surface energy have on growth mode. From analytical and numerical analysis in 1 + 1 dimensions, the interrelationship of such physical factors is revealed. Our improved understanding enables control over the growth behavior of strained-layer superlattices and heterostructures.

Modified Nextal crystallization device forin situinspection of protein crystal quality

2005 ◽  
Vol 38 (2) ◽  
pp. 396-397 ◽  
Author(s):  
Nobuhisa Watanabe
Keyword(s):  
Crystal Quality ◽  
Protein Crystal ◽  
X Rays ◽  
Resolution Limit ◽  
Physical Damage ◽  
Space Group ◽  
Cell Parameters

The modification and use of the Nextal crystallization device for checking the diffraction quality of protein crystalsin situis described. Using the modified device, crystals in the crystallization drop can be exposed to X-rays directly to observe the diffraction quality without physical damage to the crystal. If the crystals in the drop are well separated, not only the resolution limit of the crystal is estimated, but also determination of the space group and the cell parameters is possible.

IN SITU STUDIES OF EPITAXIAL GROWTH BY SYNCHROTRON X-RAY DIFFRACTION

2006 ◽  
Vol 13 (02n03) ◽  
pp. 155-166 ◽  
Author(s):  
WOLFGANG BRAUN ◽  
KLAUS H. PLOOG
Keyword(s):  
Ostwald Ripening ◽  
Crystal Surface ◽  
High Energy ◽  
Molecular Beam Epitaxy Growth ◽  
X Rays ◽  
Surface Kinetics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Kinetics Of

X-rays are ideal to study the structure of crystals due to their weak interaction with matter and in most cases allow a quantitative analysis using kinematical theory. To study the incorporation of atoms during crystal growth and to analyze the kinetics on the crystal surface high primary beam intensities available at synchrotrons are required. Our studies of the molecular beam epitaxy growth of III–V semiconductors reveal that, despite their similarity in crystal structure, the surface kinetics of GaAs (001), InAs (001) and GaSb (001) differ strongly. GaAs shows an unexpectedly large coarsening exponent outside the predicted range of Ostwald ripening models during recovery. GaSb exhibits dramatically different surface morphology variations during growth and recovery. Overgrowth of GaAs by epitaxial MnAs demonstrates the ability of X-ray diffraction to follow an interface as it is buried during heteroepitaxy, which is not possible by reflection high-energy electron diffraction.

Recrystallization of AA1050 Studied by 3DXRD

2006 ◽  
Vol 519-521 ◽  
pp. 1569-1578
Author(s):  
Dorte Juul Jensen
Keyword(s):  
Single Crystals ◽  
High Energy ◽  
Nucleation And Growth ◽  
X Rays ◽  
X Ray Diffraction ◽  
Orientation Relationships ◽  
X Ray ◽  
3 Dimensional ◽  
Kinetics Of

By 3 dimensional X-ray diffraction (3DXRD) using high energy X-rays from synchrotron sources it is possible to study in-situ the nucleation and growth during recrystallization. In this paper it is described and discussed how 3DXRD can supplement EBSP measurements of nucleation and growth. Three types of studies are considered: i) orientation relationships between nuclei and parent deformed matrix, ii) recrystallization kinetics of individual bulk grains and iii) filming of growing grains in deformed single crystals.

An In-Situ Study of the Segregation and the Strain Relaxation During Growth of Gold and Nickel Ultrathin Films

1999 ◽  
Vol 562 ◽  
Author(s):  
S. Labat ◽  
P. Gergaud ◽  
O. Thomas ◽  
B. Gilles ◽  
A. Marty
Keyword(s):  
Ultrathin Films ◽  
Strain Relaxation ◽  
High Energy ◽  
Stress And Strain ◽  
High Energy Electron ◽  
In Situ Study ◽  
Real Time Measurement ◽  
Ultrathin Layers ◽  
Large Asymmetry

ABSTRACTWe report on in-situ real time measurement of both stress and strain during growth of ultrathin layers, with submonolayer sensitivity. The in-plane parameter is measured by Reflection High Energy Electron Diffraction (RHEED) and the stress is determined via the measurement of the curvature. The system studied is Au/Ni (i.e. Au on Ni and Ni on Au). We have evidenced a large asymmetry in the two different growths: Au (on Ni) shows a progressive elastic strain relaxation whereas Ni (on Au) exhibits a strong interplay between the stress and the interfacial mixing.

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