Phase Transitions Near Surfaces Studied By Grazing Incidence Diffraction of X-Rays

1990 ◽  
Vol 208 ◽  
Author(s):  
L. Mailander ◽  
H. Dosch ◽  
J. Peisl ◽  
R. L. Johnson
Keyword(s):  
Phase Transitions ◽  
Transition Temperature ◽  
Single Crystal ◽  
Critical Behavior ◽  
Scaling Laws ◽  
Grazing Incidence ◽  
Critical Surface ◽  
X Rays ◽  
Near Surface ◽  
Grazing Incidence Diffraction

ABSTRACTWe review two different experiments in order to demonstrate the power of grazing incidence diffraction of x-rays in studying phase transitions near surfaces and to show that it is well suited to get information on structural details even from subsurface layers: We have measured the near surface critical scattering at the continuous order disorder transition of an Fe3Al single crystal which provides information on modifications of critical behavior of a bulk transition near a surface. These modifications are detectable to a considerable depth due to the diverging range of correlations. We determined three different critical surface exponents which allow, for the first time, to confirm scaling laws for near surface critical behavior.- The experiment at a (100) surface of a discontinuous ordering Cu3Au single crystal shows that the surface is wetted by a disordered layer below the transition temperature. By means of the adjustable depth sensitivity of grazing incidence scattering we were able to demonstrate that the thickness of this layer increases logarithmically when approaching the transition temperature.

Grazing Incidence X-Ray Characterization of Materials

1992 ◽  
Vol 36 ◽  
pp. 171-184 ◽  
Author(s):  
D.K. Bowen ◽  
M. Wormington
Keyword(s):  
Grazing Incidence ◽  
Experimental Techniques ◽  
X Rays ◽  
Near Surface ◽  
X Ray ◽  
Grazing Incidence Diffraction ◽  
Characterization Of Materials ◽  
Grazing Angles

AbstractA review of the methods of characterization of materials using X-rays incident at grazing angles is presented. The rationale of all such methods is the need to obtain information from near-surface regions. The methods include grazing incidence diffraction, reflectivity, diffuse scatter and fluorescence. The experimental techniques are outlined, and the information obtainable and the methods of interpretation are discussed.

Structure of the Near-Surface Waveguide Layers Produced by Diffusion of Titanium in Lithium Niobate

1999 ◽  
Vol 590 ◽  
Author(s):  
Y. Avrahami ◽  
E. Zolotoyabko ◽  
W. Sauer ◽  
T. H. Metzger ◽  
J. Peisl
Keyword(s):  
Thin Film ◽  
Lithium Niobate ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Near Surface ◽  
Structural Modifications ◽  
Grazing Incidence Diffraction ◽  
Surface Waveguide

ABSTRACTTitanium-induced structural modifications in thin waveguide layers of lithium niobate have been investigated by grazing incidence diffraction and complementary thin film techniques. The study was focused on the high-temperature phase transformation in this system and its influence on the lattice parameter changes, depending on the annealing time.

scholarly journals A multireflection and multiwavelength residual stress determination method using energy dispersive diffraction

2018 ◽  
Vol 51 (3) ◽  
pp. 732-745 ◽  
Author(s):  
Marianna Marciszko ◽  
Andrzej Baczmański ◽  
Manuela Klaus ◽  
Christoph Genzel ◽  
Adrian Oponowicz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Synchrotron Radiation ◽  
Diffraction Method ◽  
Surface Region ◽  
Grazing Incidence ◽  
High Energy ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray Diffraction ◽  
Near Surface

The main focus of the presented work was the investigation of structure and residual stress gradients in the near-surface region of materials studied by X-ray diffraction. The multireflection method was used to measure depth-dependent stress variation in near-surface layers of a Ti sample (grade 2) subjected to different mechanical treatments. First, the multireflection grazing incidence diffraction method was applied on a classical diffractometer with Cu Kα radiation. The applicability of the method was then extended by using a white synchrotron beam during an energy dispersive (ED) diffraction experiment. An advantage of this method was the possibility of using not only more than one reflection but also different wavelengths of radiation. This approach was successfully applied to analysis of data obtained in the ED experiment. There was good agreement between the measurements performed using synchrotron radiation and those with Cu Kα radiation on the classical diffractometer. A great advantage of high-energy synchrotron radiation was the possibility to measure stresses as well as thea0parameter andc0/a0ratio for much larger depths in comparison with laboratory X-rays.

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.

Near-Surface Chemical Characterization Using Grazing Incidence X-ray Fluorescence

1989 ◽  
Vol 33 ◽  
pp. 205-211 ◽  
Author(s):  
Kenji Sakurai ◽  
Atsuo lida
Keyword(s):  
Chemical Characterization ◽  
Grazing Incidence ◽  
Total Reflection ◽  
Surface Element ◽  
X Rays ◽  
Fluorescence Technique ◽  
Element Analysis ◽  
Near Surface ◽  
X Ray ◽  
Glancing Angle

External X-ray total reflection occurs when collimated X-ray beams impinge on a smooth, flat surface of matter at a small glancing angle, typically a few mrad. With respect to the X-ray fluorescence technique, total reflection experiments have allowed the trace determination of solution samples using an X-ray mirror as a sample support. The grazing incidence X-ray fluorescence technique (GIF) is also suitable for near-surface element analysis of the material, because the penetration depth of X-rays is 10-1000 Å around the critical angle.

scholarly journals Near-surface relaxation structure of annealed block copolymer film on Si substrates examined by grazing-incidence small-angle scattering utilizing soft X-rays

2011 ◽  
Vol 44 (2) ◽  
pp. 380-384 ◽  
Author(s):  
Hiroshi Okuda ◽  
Kohki Takeshita ◽  
Shojiro Ochiai ◽  
Shin-ichi Sakurai ◽  
Yoshinori Kitajima
Keyword(s):  
Block Copolymer ◽  
Small Angle ◽  
Microphase Separation ◽  
Grazing Incidence ◽  
Sample Surface ◽  
Surface Relaxation ◽  
Angle Of Incidence ◽  
X Rays ◽  
Near Surface ◽  
Si Substrates

Two-dimensional grazing-incidence small-angle X-ray scattering (GISAXS) measurements of SEBS8 block copolymer films deposited on Si(001) substrates have been performed to demonstrate depth-sensitive GISAXS utilizing soft X-rays of 1.77 keV. Remarkable elongation of the Bragg spots in theqzdirection, corresponding to microphase separation, was observed for an angle of incidence close to the critical angle. The elongation was explained in terms of the penetration depth, which limits the effective size in the direction perpendicular to the sample surface. Lattice distortion near the surface was confirmed.

EVANESCENT X-RAYS PROBING SURFACE-DOMINATED PHASE TRANSITIONS

1992 ◽  
Vol 06 (17) ◽  
pp. 2773-2808 ◽  
Author(s):  
H. DOSCH
Keyword(s):  
Free Surface ◽  
Phase Transitions ◽  
Surface Segregation ◽  
Theoretical Models ◽  
X Rays ◽  
Near Surface ◽  
Disorder Transition ◽  
Angle Scattering ◽  
Strong Surface ◽  
Experimental Findings

This article reviews the scattering of evanescent x-ray waves as they occur inside a solid in the regime of total external reflection. The theoretical and experimental details of glancing angle scattering and the use of synchrotron radiation are discussed. It is shown how strong surface disorder and surface roughness affect the Bragg scattering of these exponentially damped waves and how these scattering signals can be interpreted in a straightforward way within the distorted wave Born approximation (DWBA). The application of this novel surface technique to bulk phase transitions allows the observation of surface-dominated behaviour. This is illustrated via two examples:. 1. The discontinuous order-disorder transition in Cu 3 Au has been studied near the (001) and (111) surface by evanescent x-rays. It turns out that the order parameter close to the free surface of the alloy decays in a very pronounced way upon approaching the transition temperature. The quantitative analysis of the evanescent superlattice intensity is compatible with a wetting phenomenon. 2. The critical phenomena associated with the continuous order-disorder transition in Fe 3 Al become distinctly modified due to the presence of a free surface. By applying the evanescent wave method three new universal surface exponents β1, γ11 and η‖ could be determined. This allows for the first time a critical exprimental test of surface scaling relations which turn out to be in good agreement with the experimental findings. At the surface of binary alloys surface segregation phenomena occur which complicate the experimental observation of near-surface ordering and disordering phenomena as well as the theoretical models which have to account for these effects. Some implications of these surface effects is briefly presented.

Sign in / Sign up

Export Citation Format

Share Document