Near-surface critical x-ray scattering fromFe3Al

1990 ◽  
Vol 64 (21) ◽  
pp. 2527-2530 ◽  
Author(s):  
L. Mailänder ◽  
H. Dosch ◽  
J. Peisl ◽  
R. L. Johnson
Keyword(s):  
Near Surface ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Strain Analysis in Thin La1−xCaxMnO3 Films by Grazing Incidence X-ray Scattering

1999 ◽  
Vol 602 ◽  
Author(s):  
M. Petit ◽  
L. J. Martinez-Miranda ◽  
M. Rajeswari ◽  
A. Biswas ◽  
D. J. Kang ◽  
...  
Keyword(s):  
Film Thickness ◽  
Lattice Mismatch ◽  
Compressive Strain ◽  
Strain Analysis ◽  
Grazing Incidence ◽  
Relaxation Processes ◽  
Near Surface ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

AbstractWe have performed depth profile analyses of the lattice parameters in epitaxial thin films of La1−xCaxMno3 (LCMO), where x = 0.33 or 0.3, to understand the evolution of strain relaxation processes in these materials. The analyses were done using Grazing Incidence X-ray Scattering (GIXS) on films of different thicnesses on two different substrates, (100) oriented LaAlO3 (LAO), with a lattice mismatch of ∼2% and (110) oriented NGO, with a lattice mismatch of less than 0.1%. Films grown on LAO can exhibit up to three in-plane strained lattice constants, corresponding to a slight orthorhombic distortion of the crystal, as well as near-surface and columnar lattice relaxation. As a function of film thickness, a crossover from a strained film to a mixture of strained and relaxed regions in the film occurs in the range of 700 Å. The structural evolution at this thickness coincides with a change in the resistivity curve near the metalinsulator transition. The in-plane compressive strain has a range of 0.2 – 1.5%, depending on the film thickness for filsm in the range of 400 - 1500 A.

Diffuse X-Ray Scattering Study of Defects Created by KeV Ion Implants In Si

1996 ◽  
Vol 439 ◽  
Author(s):  
P. J. Partyka ◽  
R. S. Averback ◽  
K. Nordlund ◽  
I. K. Robinson ◽  
D. Walko ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Irradiation Damage ◽  
Complex Nature ◽  
Computational Framework ◽  
Near Surface ◽  
X Ray ◽  
Simulation Techniques ◽  
X Ray Scattering ◽  
Surface Measurements ◽  
Ray Scattering

AbstractDiffuse x-ray scattering (DXS) and computer simulation techniques were employed to investigate the defect structure produced in Si by low keV ion and MeV electron irradiations. DXS measurements were performed for keV Ga and He implants, demonstrating the ability of the technique to provide both bulk and near-surface measurements at defect concentrations of about 1000 ppm. A rigorous analysis of these results is complicated due to the complex nature of the ion damage in Si. A computer simulation framework is developed to aid in the analysis of this data. In this technique, defects are simulated and their strain fields are calculated by simply relaxing the atoms around the defect to their equilibrium positions. The diffuse scattering is then calculated from the strain field, and the results are compared to the experimental measurements. Computer simulations are presented here only for the case of electron irradiation damage and compared to published measurements. Application of the technique to more complicated structures is planned and should pose no serious problems in the computational framework already developed.

X-RAY SCATTERING STUDIES OF CHARGE STRIPES IN La2-xSrxNiO4 (x=0.20-0.33)

2002 ◽  
Vol 16 (11n12) ◽  
pp. 1633-1640 ◽  
Author(s):  
P. D. HATTON ◽  
M. E. GHAZI ◽  
S. B. WILKINS ◽  
P. D. SPENCER ◽  
D. MANNIX ◽  
...  
Keyword(s):  
Correlation Length ◽  
Surface Region ◽  
Crystalline Lattice ◽  
X Rays ◽  
Near Surface ◽  
X Ray ◽  
X Ray Scattering ◽  
Charge Stripe ◽  
A Charge ◽  
Ray Scattering

The La 2-x Sr x NiO 4 system is isostructural with the high T C superconducting cuprate La 2-x Sr x CuO 4 and is a prototypical system for the understanding of strongly correlated electron-phonon coupling, and the resultant effects on material properties. X-ray scattering studies have been performed on La5/3Sr1/3NiO4 that demonstrate the two-dimensional nature of these charge stripes. Such studies, demonstrate the very high correlation length of the stripes (~ 2000 Å) at low temperatures. We have undertaken a series of experiments measuring the wavevector and charge stripe correlation length on a variety of crystals with the compositions La 2-x Sr x NiO 4 (x=0.20, 0.25, 0.275, 0.30 and 0.33) using ~10 keV X-rays. The results demonstrate that for x=0.275, and above, the charge stripes are highly correlated in a well-ordered crystalline lattice. Measurements of the incommensurability, ε, as a function of temperature for the series revealed that it is commensurate and temperature independent for the x=0.33 sample. For other compositions it is incommensurate and also temperature dependent. However for the x=0.20 and 0.25 crystals a much reduced correlation length was observed suggestive of a charge stripe glass. However, such experiments are sensitive to such charge ordering only in the near (top few micron) surface region. High energy X-rays however can probe the charge stripe ordering within the bulk of the single crystal by utilising the dramatic increase in penetration depth. We have used 130 keV X-rays and demonstrate that in La5/3Sr1/3NiO4 the charge stripes are far less correlated in the bulk than in the near surface region. This reduced correlation length (~300 Å), consistent with neutron scattering measurements, is indicative of a charge stripe glass, reminiscent of that observed below x=0.25, in the near surface region.

scholarly journals X-ray Reflectometry and Related Surface Near X-ray Scattering Methods

2014 ◽  
Vol 228 (10-12) ◽  
Author(s):  
Oliver H. Seeck
Keyword(s):  
Grazing Incidence ◽  
Surface Structures ◽  
Wave Optics ◽  
Near Surface ◽  
X Ray ◽  
Full Theory ◽  
X Ray Scattering ◽  
Grazing Incidence Diffraction ◽  
Non Destructive ◽  
Ray Scattering

AbstractSurface sensitive X-ray scattering methods are mostly non-destructive tools which are frequently used to investigate the nature of thin films, interfaces and artificial near surface structures. Discussed here are diffraction based methods, namely reflectometry and the related techniques grazing incidence diffraction and crystal truncation rod measurements. For the experiment, an X-ray beam is diffracted from surface near structures of the sample and detected by adequate detectors. To analyze the data the according X-ray scattering theory has to be applied. The full theory of surface sensitive X-ray scattering is complex and based on general considerations from wave optics. However, instructive insights into the scattering processes are provided by the Born-approximation which in many cases yields sufficient results. The methods are applied to solve the structure of a mercury-electrolyte interface during a chemical reaction and to determine the strain distribution in surface near SiGe quantum dots.

Structural properties of ultra-low-energy ion-implanted silicon studied by combined X-ray scattering methods

2006 ◽  
Vol 39 (4) ◽  
pp. 571-581 ◽  
Author(s):  
L. Capello ◽  
T. H. Metzger ◽  
V. Holý ◽  
M. Servidori ◽  
A. Malachias
Keyword(s):  
Structural Characterization ◽  
Bragg Reflection ◽  
Complete Characterization ◽  
Low Energy ◽  
Diffuse Intensity ◽  
Near Surface ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

The use of a combination of X-ray scattering techniques for the complete characterization of ultra-low-energy (E< 5 keV) implanted Si is discussed. Grazing incidence diffuse X-ray scattering (GI-DXS) reveals the properties of the defects confined within thin crystalline layers with depth resolution. Due to the weak diffuse intensity arising from such defects, the high brilliance of synchrotron radiation is required. GI-DXS proved to be particularly well suited for the investigation of the so-called `end-of-range' defects. In a complementary way, X-ray diffraction (XRD) in the vicinity of the 004 Bragg reflection is sensitive to the distribution of the strain in the Si lattice in the direction perpendicular to the sample surface. The structural characterization is complemented by the electron density profile of the near-surface amorphous region provided by specular reflectivity (SR). It will be shown that only by merging the results obtained with GI-DXS, XRD and SR, is it possible to obtain the detailed structural characterization of the implanted Si samples.

Structural characterization of SiGe and SiGe:C heterostructures using a combination of X-ray scattering methods

2004 ◽  
Vol 19 (1) ◽  
pp. 49-52 ◽  
Author(s):  
J. F. Woitok
Keyword(s):  
Structural Characterization ◽  
Surface Region ◽  
X Ray Diffraction ◽  
Near Surface ◽  
Xrd Pattern ◽  
X Ray ◽  
X Ray Scattering ◽  
Single Method ◽  
Ray Scattering

This study is about the structural properties of SiGe and SiGe:C heteroepitaxial layers on Si (001). The structural characterization is based on the application of complementary information content of X-ray scattering techniques like high-resolution X-ray diffraction (XRD), X-ray reflectivity (XRR), and X-ray diffuse scattering (XDS). One main focus of the analysis is to derive a sample model that sufficiently describes all experimental datasets. In addition, the reliability of parameters extracted by just one single method is discussed. It turned out that XRR is more sensitive to the near surface region, indicating the presence of surface roughness and density gradients that do not significantly affect the XRD pattern.

Diffuse X-Ray Scattering Study of Defects Created by keV Ion Implants in Si

1996 ◽  
Vol 438 ◽  
Author(s):  
P. J. Partyka ◽  
R. S. Averback ◽  
K. Nordlund ◽  
I. K. Robinson ◽  
D. Walko ◽  
...  
Keyword(s):  
Computer Simulation ◽  
Irradiation Damage ◽  
Complex Nature ◽  
Computational Framework ◽  
Near Surface ◽  
X Ray ◽  
Simulation Techniques ◽  
X Ray Scattering ◽  
Surface Measurements ◽  
Ray Scattering

AbstractDiffuse x-ray scattering (DXS) and computer simulation techniques were employed to investigate the defect structure produced in Si by low keV ion and MeV electron irradiations. DXS measurements were performed for keV Ga and He implants, demonstrating the ability of the technique to provide both bulk and near-surface measurements at defect concentrations of about 1000 ppm. A rigorous analysis of these results is complicated due to the complex nature of the ion damage in Si. A computer simulation framework is developed to aid in the analysis of this data. In this technique, defects are simulated and their strain fields are calculated by simply relaxing the atoms around the defect to their equilibrium positions. The diffuse scattering is then calculated from the strain field, and the results are compared to the experimental measurements. Computer simulations are presented here only for the case of electron irradiation damage and compared to published measurements.1 Application of the technique to more complicated structures is planned and should pose no serious problems in the computational framework already developed.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

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