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 Synthesis of CdS nanocrystals in polymeric films studied by in-situ GID and GISAXS

2015 ◽  
Vol 1810 ◽  
Author(s):  
Tiziana Di Luccio ◽  
Dina Carbone ◽  
Silvia Masala ◽  
Karthik Ramachandran ◽  
Julie Kornfield
Keyword(s):  
Hexagonal Lattice ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
Polymeric Films ◽  
Diffraction Intensity ◽  
Cds Nanocrystals ◽  
Grazing Incidence Diffraction ◽  
Angle Scattering ◽  
Precursor Structure

ABSTRACTIn this work, we describe the synthesis of CdS nanocrystals in thin polymeric films by in-situ Grazing Incidence Diffraction (GID) and Grazing Incidence Small Angle Scattering (GISAXS). The 2D GISAXS patterns indicate how the precursor structure is altered as the temperature is varied from 25°C to 300°C. At 150°C, the CdS nanocrystals start to arrange themselves in a hexagonal lattice with a lattice parameter of 27 Å. The diffraction intensity from the hexagonal lattice reaches a maximum at 170°C and decreases steadily upon further heating above 220°C indicating loss of symmetry. Correspondingly, the GID scans at 170°C show strong crystalline peaks from cubic CdS nanocrystals that are about 2 nm size. The results indicate that a temperature of 170°C is sufficient to synthesize CdS nanocrystals without degradation of the polymer matrix (Topas) in thin films (about 30nm).

Strain and Shape in Self-Assembled Quantum Dots Studied by X-Ray Grazing Incidence Diffraction

1998 ◽  
Vol 524 ◽  
Author(s):  
I. Kegel ◽  
T. H. Metzger ◽  
J. Peisl ◽  
P. Fratzl ◽  
A. Lorke ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
Reciprocal Space Mapping ◽  
X Ray ◽  
Surface Reflection ◽  
Grazing Incidence Diffraction ◽  
Shape Effects ◽  
Outer Perimeter ◽  
Highly Strained

ABSTRACTWe have developed a method to determine the relationship between strain and lateral size of coherent self-organized quantum dots. In our approach, X-ray grazing incidence diffraction is used to collect information on strain and shape effects in the vicinity of a prominent surface reflection. We demonstrate that for highly strained nano-scale islands it is possible to separate strain-induced and form factor-induced scattering without comparing different reflections. Experimental data from InAs on GaAs(100) quantum dots is discussed with respect to this model. Reciprocal space mapping around the (220) surface reflection shows a linear relationship between relaxation from the substrate lattice parameter and the outer perimeter of the dot. In addition, the functional form of the gradient of relaxation is found to be nonmonotonous and rapidly increasing towards the tip of the dot.

scholarly journals Conductivity Transitions of La0.7Sr0.3MnO3±δ and La0.6Sr0.4Co0.2Fe0.8O3−δ in Ce0.9Gd0.1O2−δ Matrix for Dual-Phase Oxygen Transport Membranes

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 712
Author(s):  
Thuy Linh Pham ◽  
Ji Haeng Yu ◽  
Jong-Sook Lee
Keyword(s):  
Activation Energy ◽  
Oxygen Transport ◽  
Thermal Hysteresis ◽  
Small Polaron ◽  
Lattice Parameter ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Arrhenius Behavior ◽  
Van Der Pauw ◽  
Transition Points

Using van der Pauw method, the conductivity of disk samples of La0.7Sr0.3MnO3±δ (LSM) and La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) in a Ce0.9Gd0.1O2−δ (GDC) matrix was accurately quasi-continuously measured over 800 °C to −73 °C, and the transition points in Arrhenius behavior were systematically obtained from the extremum points of the second derivatives. While LSM-containing samples showed reproducible conductivity trajectories, the LSCF system exhibited unsystematic changes which may be related to the substantial oxidation/reduction reactions accompanying the ferroelastic–paraelastic transitions with a substantial thermal hysteresis at 650 °C to 750 °C, corresponding to conductivity maxima. A sudden decrease in activation energies on cooling corresponds to the para-to-ferromagnetic, weak insulator–metal transitions and the Curie temperature of LSM appears to gradually decrease in composites to 90 °C, while LSCF composites exhibit blurred transitions at approximately −40 °C. Relatively insulating paramagnetic phases are characterized by activation energy values ~0.2 eV, change to the high temperature phase exhibiting activation energy 0.1 eV for small polaron hopping mechanisms at 300 °C to 500 °C with increasing GDC content in the LSM composites and by two transitions at ∼60 °C and ∼245 °C for the LSCF composites. LSCF single phase shows distinctly lower transition points which appear to match with the singularly large c lattice parameter whereas the composites exhibit decreasing c with LSCF amount together with increasing lattice parameter of GDC. Van der Pauw conductivity is a feasible and sensitive in situ tool for monitoring the status of oxygen transport membranes.

Depth Profiling of Molybdenum Thin Films Using Grazing Incidence X-Ray Scattering

1993 ◽  
Vol 317 ◽  
Author(s):  
Sandra G. Malhotra ◽  
Z. Rek ◽  
M. Vill ◽  
O.P. Karpenko ◽  
S.M. Yalisove ◽  
...  
Keyword(s):  
Thin Film ◽  
Depth Profiling ◽  
Grazing Incidence ◽  
Lattice Parameter ◽  
Three Dimensions ◽  
X Ray ◽  
X Ray Scattering ◽  
Average Change ◽  
Principal Strains ◽  
Ray Scattering

ABSTRACTIt is important that inherent strains (or stresses) be controlled during thin film processing. This study used grazing incidence x-ray scattering (G1XS) to determine the strain gradient present in a ∼1700 Å sputtered molybdenum thin film. In particular, the gradient in the hydrostatic strain was Measured. This observation corresponded to assessing the average change in the lattice parameter as a function of depth throughout the thickness of the film. In addition, the strain ellipsoids, which represent the state of strain in three dimensions, were calculated as a function of film depth. It was shown that the strain varied throughout the ∼1700 Å Mo film thickness and that the principal strains were anisotropic, with one principal strain much larger than the others in Magnitude.

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.

Crystal Structure of the High-Temperature Phase of a Compound Sr2ZnWO6

1992 ◽  
Vol 7 (4) ◽  
pp. 226-227 ◽  
Author(s):  
Fu Zhengmin ◽  
Li Wenxiu
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Lattice Parameter ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
X Ray ◽  
Cubic System ◽  
Measured Density

AbstractThe crystal structure of the high-temperature phase of Sr2ZnWO6 prepared by air quenching from 1200° C has been determined by means of X-ray powder diffraction. β-Sr2ZnWO6 belongs to the cubic system, with space group Fm3m and a lattice parameter a = 7.9266 Å at room temperature. Its measured density is Dm = 6.93g/cm3, and each unit cell contains four formula weights.

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.

scholarly journals Crystallographic and optical study of PbHfO3 crystals

2017 ◽  
Vol 50 (2) ◽  
pp. 378-384 ◽  
Author(s):  
S. Huband ◽  
A. M. Glazer ◽  
K. Roleder ◽  
A. Majchrowski ◽  
P. A. Thomas
Keyword(s):  
Intermediate Phase ◽  
Lattice Parameter ◽  
High Temperature Phase ◽  
Unit Cell ◽  
Tetragonal Symmetry ◽  
Orthorhombic Symmetry ◽  
Temperature Phase ◽  
Optical Study ◽  
X Ray Diffraction ◽  
X Ray

The symmetry of the intermediate high-temperature phase of PbHfO3 has been determined unambiguously to be orthorhombic using a combination of high-resolution X-ray diffraction and birefringence imaging microscopy measurements of crystal plates. While lattice parameter measurements as a function of temperature in the intermediate phase are consistent with either orthorhombic or tetragonal symmetry, domain orientations observed in birefringence imaging microscopy measurements utilizing the Metripol system are only consistent with orthorhombic symmetry with the unit cell in the rhombic orientation of the pseudocubic unit cell.

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