Structures of Zr2Co11 and HfCo7 intermetallic compounds

1991 ◽  
Vol 24 (6) ◽  
pp. 1023-1026 ◽  
Author(s):  
B. G. Demczyk ◽  
S. F. Cheng
Keyword(s):  
Crystal Structure ◽  
Intermetallic Compounds ◽  
Convergent Beam Electron Diffraction ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Beam Electron ◽  
Long Period ◽  
Transmission Electron ◽  
Unit Cells ◽  
Convergent Beam

The crystal structures of Zr2CO11 and HfCo7 intermetallic compounds were examined by transmission electron microscopy using both selected-area and convergent-beam electron diffraction. Results show that both have an orthorhombic crystal structure, space group Pcna. The unit cells of both compounds appear to be comprised of two long-period superlattices in antiphase relation to one another along [001].

A library of convergent-beam electron diffraction patterns

1986 ◽  
Vol 44 ◽  
pp. 688-691
Author(s):  
John F. Mansfield
Keyword(s):  
Electron Diffraction ◽  
Materials Science ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Transmission Electron ◽  
Yield Information ◽  
Analytical Electron ◽  
Diffraction Patterns ◽  
Convergent Beam ◽  
Electron Energy Loss

One of the most important advancements of the transmission electron microscopy (TEM) in recent years has been the development of the analytical electron microscope (AEM). The microanalytical capabilities of AEMs are based on the three major techniques that have been refined in the last decade or so, namely, Convergent Beam Electron Diffraction (CBED), X-ray Energy Dispersive Spectroscopy (XEDS) and Electron Energy Loss Spectroscopy (EELS). Each of these techniques can yield information on the specimen under study that is not obtainable by any other means. However, it is when they are used in concert that they are most powerful. The application of CBED in materials science is not restricted to microanalysis. However, this is the area where it is most frequently employed. It is used specifically to the identification of the lattice-type, point and space group of phases present within a sample. The addition of chemical/elemental information from XEDS or EELS spectra to the diffraction data usually allows unique identification of a phase.

Convergent-beam electron diffraction at high spatial resolution

1992 ◽  
Vol 50 (2) ◽  
pp. 1152-1153 ◽  
Author(s):  
J W Steeds
Keyword(s):  
Electron Diffraction ◽  
High Temperature Superconductors ◽  
Bloch Wave ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Energy Filtering ◽  
Small Probe ◽  
Transmission Electron ◽  
Electron Microscopes ◽  
Convergent Beam

That the techniques of convergent beam electron diffraction (CBED) are now widely practised is evident, both from the way in which they feature in the sale of new transmission electron microscopes (TEMs) and from the frequency with which the results appear in the literature: new phases of high temperature superconductors is a case in point. The arrival of a new generation of TEMs operating with coherent sources at 200-300kV opens up a number of new possibilities.First, there is the possibility of quantitative work of very high accuracy. The small probe will essentially eliminate thickness or orientation averaging and this, together with efficient energy filtering by a doubly-dispersive electron energy loss spectrometer, will yield results of unsurpassed quality. The Bloch wave formulation of electron diffraction has proved itself an effective and efficient method of interpreting the data. The treatment of absorption in these calculations has recently been improved with the result that <100> HOLZ polarity determinations can now be performed on III-V and II-VI semiconductors.

scholarly journals Structural Defects in Laterally Overgrown GaN Layers Grown on Non-polar Substrates

2006 ◽  
Vol 955 ◽  
Author(s):  
Zuzanna Liliental-Weber ◽  
X. Ni ◽  
H. Morkoc
Keyword(s):  
Large Angle ◽  
Stacking Faults ◽  
Growth Direction ◽  
Convergent Beam Electron Diffraction ◽  
Structural Defects ◽  
Threading Dislocations ◽  
Beam Electron ◽  
Transmission Electron ◽  
Wing Width ◽  
Convergent Beam

ABSTRACTTransmission electron microscopy was used to study defects in lateral epitaxial layers of GaN which were overgrown on a template of a-plane (1120) GaN grown on (1102) r-plane Al2O3. A high density of basal stacking faults is formed in these layers because the c-planes of wurtzite structure are arranged along the growth direction. Density of these faults is decreasing at least by two orders of magnitude lower in the wings compared to the seed areas. Prismatic stacking faults and threading dislocations are also observed, but their densities drastically decrease in the wings. The wings grow with opposite polarities and the Ga-wing width is at least 6 times larger than N-wing and coalescence is rather difficult. Some tilt and twist was detected using Large Angle Convergent Beam Electron Diffraction.

Plan-View CBED Studies of Nio-Zro2(CaO) Interfaces

1989 ◽  
Vol 159 ◽  
Author(s):  
V.P. Dravid ◽  
M.R. Notis ◽  
C.E. Lyman ◽  
A. Revcolevschi
Keyword(s):  
Electron Diffraction ◽  
Convergent Beam Electron Diffraction ◽  
Low Energy ◽  
Directionally Solidified ◽  
Plan View ◽  
Beam Electron ◽  
Transmission Electron ◽  
Interfacial Defects ◽  
Convergent Beam ◽  
Lamellar Interfaces

ABSTRACTLow energy lamellar interfaces in the directionally solidified eutectic (DSE) NiO-ZrO2(CaO) have been investigated using transmission electron diffraction and imaging. The symmetry of this bicrystal and an aspect of interfacial relaxations in the form of symmetry lowering in-plane rigid body translation (RBT) have been explored by performing convergent beam electron diffraction (CBED) experiments of plan-view bicrystals. Edge-on interfaces have also been studied by conventional and high resolution transmission electron microscopy (CTEM and HRTEM respectively), and electron diffraction fine structure analysis. Despite certain experimental difficulties due to interfacial defects and strain, plan-view CBED patterns offered valuable information concerning bicrystal symmetry and indicated no symmetry lowering RBT in this bicrystal. The suitability of plan-view CBED is briefly discussed in view of its potential as a technique to determine bicrystal symmetry and RBT.

Nanoscopic unequivocal analysis of twinned crystal structures with tetragonal or orthogonal unit cells by electron microdiffraction

1999 ◽  
Vol 32 (3) ◽  
pp. 397-403 ◽  
Author(s):  
M. Leicht ◽  
T. Remmele ◽  
D. Stenkamp ◽  
H. P. Strunk
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Lattice Parameters ◽  
Transmission Electron ◽  
Unit Cells ◽  
Convergent Beam ◽  
Chalcogenide Compound ◽  
Habit Planes ◽  
Twinned Crystal Structure ◽  
Electron Microdiffraction

In this study, a particular type of nanoscopic twinned crystal structure which can occur in any tetragonal or orthogonal crystal structure with a ratio of lattice parameters c/a=c/b=2 is presented. This type of twinning is characterized by twin components whosecaxes are oriented perpendicular to one another, by twin-habit planes parallel to {102} planes, and by a superstructure along the twin boundaries which is described by orthogonal unit cells with lattice parameters 2a, 2a,a. Furthermore, the suitability of electron microdiffraction, a diffraction technique of transmission electron microscopy (TEM) with a moderately convergent beam, for the analysis of such twinned crystal structures is demonstrated. For this demonstration, electron microdiffraction is applied to the chalcogenide compound Cu2In3Se5, which indeed exhibits the proposed twinned crystal structure.

Characterization Of APB's In GaP

1996 ◽  
Vol 442 ◽  
Author(s):  
Dov Cohen ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Convergent Beam Electron Diffraction ◽  
Antiphase Boundaries ◽  
Beam Electron ◽  
Transmission Electron ◽  
Convergent Beam ◽  
Crystallographic Orientations

AbstractAntiphase boundaries in GaP crystals epitactically grown on Si (001) have been characterized using transmission electron microscopy. Convergent-beam electron diffraction was used to identify the antiphase-related grains. The antiphase boundaries were observed to adopt facets parallel to specific crystallographic orientations. Furthermore, stacking-fault-like contrast was observed along the interface suggesting that the domains may be offset from one another by a rigid-body lattice translation.

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