Experimental Determination Of Relaxation Of Interphase Interfaces In Oxide Eutectics

1991 ◽  
Vol 238 ◽  
Author(s):  
Vinayak P. Dravid ◽  
V. Ravikumar ◽  
G. Dhalenne ◽  
A. Revcolevschi
Keyword(s):  
Experimental Determination ◽  
Interface Structure ◽  
Low Energy ◽  
Three Dimensions ◽  
Directionally Solidified ◽  
Lamellar Morphology ◽  
Analytical Tem ◽  
Directionally Solidified Eutectics

ABSTRACTInterphase interfaces in the directionally solidified eutectics.(DSEs) of NiO-ZrO2(CaO), NiO-Y2O3 and MnO-ZrO2 have been investigated using a variety of TEM techniques. The unique lamellar morphology of the DSEs allows characterization of interfaces and identification of relaxations along multiple directions, aiding visualization of interface structure in three dimensions. Possible low energy interface orientations were identified through examination of facets. The low energy interface planes almost invariably correspond to polar surfaces of adjacent crystals. An attempt has been made to experimentally identify the variety of interfacial relaxation mechanisms using a variety of analytical TEM techniques and only HRTEM results are summarized in this paper. It was found that most of the DSE systems exhibit very little relaxation and possess tight interface cores.

Atomic Structure Determination of Nio-Y2O3 Interfaces by HRTEM

1997 ◽  
Vol 3 (S2) ◽  
pp. 649-650
Author(s):  
E.C. Dickey ◽  
V.P. Dravid
Keyword(s):  
Three Dimensional ◽  
Interface Structure ◽  
Low Energy ◽  
Directionally Solidified ◽  
Research Initiative ◽  
Imaging And Spectroscopy ◽  
Electron Imaging ◽  
Directionally Solidified Eutectics ◽  
Interface Structures ◽  
Oxide Composites

The investigation of interfaces between NiO and Y2O3 is part of a research initiative to understand low-energy heterophase interface structures between different oxide materials. In-situ oxide composites formed by the directional solidification of pseudo-binary eutectics are used as model materials in this study because they are amenable to chemical and structural characterization at the atomic length-scale. Previously, interfaces in NiO-ZrO2(cubic) directionally solidified eutectics (DSEs) were examined by various electron imaging and spectroscopy techniques to reveal the three-dimensional interface structure.[l] The second DSE system studied, NiO-Y2O3,[2] was chosen because it is very similar in crystallography to NiO-ZrO2(cubic). The goal of this second, analogous study is not only to understand the NiO-Y2O3 interface structure but, by comparing the results to NiO-ZrO2, is to draw more general conclusions about low energy oxide-oxide interfaces. Table one compares the crystallography of the NiO-ZrO2 and the NiO-Y2O3 DSEs.

Determination of interface width using EELS fine structure changes

1991 ◽  
Vol 49 ◽  
pp. 730-731
Author(s):  
Vinayak P. Dravid ◽  
M.R. Notis ◽  
C.E. Lyman
Keyword(s):  
Fine Structure ◽  
Materials Science ◽  
Input Parameter ◽  
Core Loss ◽  
Directionally Solidified ◽  
Interface Width ◽  
Structure Changes ◽  
Important Input ◽  
Directionally Solidified Eutectics

The concept of interfacial width is often invoked in many materials science phenomena which relate to the structure and properties of internal interfaces. The numerical value of interface width is an important input parameter in diffusion equations, sintering theories as well as in many electronic devices/processes. Most often, however, this value is guessed rather than determined or even estimated. In this paper we present a method of determining the effective structural and electronic- structural width of interphase interfaces using low- and core loss fine structure effects in EELS spectra.The specimens used in the study were directionally solidified eutectics (DSEs) in the system; NiO-ZrO2(CaO), NiO-Y2O3 and MnO-ZrO2(ss). EELS experiments were carried out using a VG HB-501 FE STEM and a Hitachi HF-2000 FE TEM.

Local bond order parameters for accurate determination of crystal structures in two and three dimensions

2018 ◽  
Vol 20 (42) ◽  
pp. 27059-27068 ◽  
Author(s):  
Hossein Eslami ◽  
Parvin Sedaghat ◽  
Florian Müller-Plathe
Keyword(s):  
Crystal Structures ◽  
Bond Order ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Order Parameters ◽  
Three Dimensions ◽  
Local Order ◽  
Crystalline Structures

Local order parameters for the characterization of liquid and different two- and three-dimensional crystalline structures are presented.

Structure Determination of Clusters Formed in Ultra-Low Energy High-Dose Implanted Silicon

2005 ◽  
Vol 108-109 ◽  
pp. 303-308 ◽  
Author(s):  
N. Cherkashin ◽  
Martin J. Hÿtch ◽  
Fuccio Cristiano ◽  
A. Claverie
Keyword(s):  
Electron Microscopy ◽  
Geometric Phase ◽  
Low Energy ◽  
High Dose ◽  
Dislocation Loops ◽  
Weak Beam ◽  
Transmission Electron ◽  
Geometric Phase Analysis

In this work, we present a detailed structural characterization of the defects formed after 0.5 keV B+ implantation into Si to a dose of 1x1015 ions/cm2 and annealed at 650°C and 750°C during different times up to 160 s. The clusters were characterized by making use of Weak Beam and High Resolution Transmission Electron Microscopy (HRTEM) imaging. They are found to be platelets of several nanometer size with (001) habit plane. Conventional TEM procedure based on defect contrast behavior was applied to determine the directions of their Burger’s vectors. Geometric Phase Analysis of HRTEM images was used to measure the displacement field around these objects and, thus, to unambiguously determine their Burger’s vectors. Finally five types of dislocation loops lying on (001) plane are marked out: with ] 001 [1/3 ≅ b and b ∝ [1 0 1], [-1 0 1], [0 1 1], [0 -1 1].

Characterization of Surface Defect Structure by Low Energy Electron Diffraction

1984 ◽  
Vol 41 ◽  
Author(s):  
J. F. Wendelken ◽  
G. -C. Wang ◽  
J. M. Pimbley ◽  
T. -M. Lu
Keyword(s):  
Electron Beam ◽  
Electron Diffraction ◽  
Surface Defect ◽  
Low Energy ◽  
Experimental Results ◽  
Energy Electron ◽  
Low Energy Electron Diffraction ◽  
Low Energy Electron

AbstractLow energy electron diffraction is a surface sensitive tool which is most widely used for the determination of surface symmetries and equilibrium atomic positions. Experimental and theoretical advances made in the past five years make it possible now to use LEED also for the characterization of a wide variety of surface defect structures. In this paper a variety of experimental results involving analysis of diffracted electron beam shapes as a function of primary electron beam energy, adsorbate coverage, crystal tem-perature and ordering time are presented. These experimental results coupled with kinematic theory, allow the determination of step density, size and shape of reconstruction domains and overlayer islands, island size distribution in an overlayer during growth, and the mode of growth.

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