Planar defects in β-iron disilicide (β-FeSi2) analyzed by transmission electron microscopy and modeling

1992 ◽  
Vol 25 (2) ◽  
pp. 122-128 ◽  
Author(s):  
Y. Zheng ◽  
A. Taccoen ◽  
J. F. Petroff
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Structural Model ◽  
Stacking Faults ◽  
Planar Defects ◽  
Iron Disilicide ◽  
Defect Position ◽  
Transmission Electron ◽  
Lattice Images ◽  
Diffraction Patterns

Microplanar defects were observed in β-iron disilicide by transmission electron microscopy. They were identified as (100)[011]/2 intrinsic stacking faults by means of electron diffraction patterns and observed in high-resolution lattice images. A structural model of the faults is proposed here in setting the defect position at x = ¼ within the cell.

scholarly journals Synchysite-(Ce) from Cinquevalli (Trento, Italy): Stacking Disorder and the Polytypism of (Ca,REE)-Fluorcarbonates

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 77 ◽  
Author(s):  
Giancarlo Capitani
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stacking Faults ◽  
Stacking Sequence ◽  
Transmission Electron ◽  
Unit Cells ◽  
Cell Refinement ◽  
Diffraction Patterns ◽  
Microscopy Images ◽  
Stacking Disorder

Synchysite-(Ce) at Cinquevalli occurs as fine needles intergrown with quartz in quartz-dikes and in association with altered K-feldspar and oxidized chalcopyrite as major constituents. Synchysite-(Ce) [Ca1.00(Ce0.43La0.26Nd0.17Y0.07Pr0.04Sm0.02Gd0.01)Σ=1.00(CO3)2(F0.58(OH)0.42)], shows an overgrowth rim of bastnäsite-(Ce) [(Ce0.34La0.25Nd0.17Pb0.07C a0.06Y0.06Pr0.04S m0.02Gd0.01)Σ=1.00C O3(F0.75(OH)0.25)]. Unit cell refinement of synchysite (C2/c) and bastnäsite (P62c) led to a = 12.272(4), b = 7.100(2), c = 18.640(5) Å, β = 102.71(5)°, and a = 7.085(1), c = 9.746(2) Å, respectively. Polysomatic faults are sporadic, but polytypic disorder is widespread. High resolution transmission electron microscopy images taken along [100] or ⟨130⟩ show an apparent order and the related diffraction patterns are streak-free. Conversely, along [010] or ⟨110⟩, a high density of stacking faults is observed and the related diffraction patterns show hhl rows with h ≠ 3n affected by streaks. No ordered domain larger than a few unit cells was detected. The stacking sequence of (Ca,REE)-fluorcarbonates can be compared with subfamily-B mica polytypes (2M2, 2O and 6H), which are characterized by n·60° (n = odd) rotations. Subfamily-A polytypes (1M, 2M1 and 3T), characterized by n·60° (n = even) rotations, should not be possible. Synchysite, characterized by ±60° rotations, can be likened to the 2M2 polytype.

TEMTUTOR - a Teaching Multimedia Program for TEM

1997 ◽  
Vol 3 (S2) ◽  
pp. 1161-1162
Author(s):  
V.-T. Kuokkala ◽  
T.K. Lepistö
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Stacking Faults ◽  
Teaching Tool ◽  
Formation Processes ◽  
Multimedia Program ◽  
Transmission Electron ◽  
Hands On ◽  
Diffraction Patterns

Teaching of transmission electron microscopy usually includes both lectures on the contrast theories, electron diffraction, etc., and practical hands-on operation of the microscope. The number of students attending the lectures is normally unlimited, but at the microscope, only a few persons can work at the same time. Since the microscopes are expensive, it would be of a great help if cheaper 'training' microscopes with basic imaging and diffraction capabilities were available. These functions, in fact, can quite easily be realized with fast personal computers and work stations, where the simulation of transmission electron micrographs and related diffraction patterns can help the student better understand the image formation processes. Adding text, audio and video help capabilities to the program, it can be made an efficient supplemental teaching tool.TemTutor for Windows is based on microScope for Windows, which is a BF/DF TEM micrograph simulation program for dislocations and stacking faults.

The Defect Structures of Fe9S10

1983 ◽  
Vol 31 ◽  
Author(s):  
Thao A. Nguyen ◽  
Linn W. Hobbs
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stacking Faults ◽  
Defect Structures ◽  
Transmission Electron ◽  
Vacancy Ordering ◽  
Different Types ◽  
Lattice Images ◽  
Antiphase Domains ◽  
Complex Features

ABSTRACTThe defect structures of Fe9S10 have been studied by high-resolution transmission electron microscopy. Lattice images of the 3C and 4C superstructures and at least one other phase, which has not been previously reported, were observed. It has been found that the 4C superstructure transforms into the 3C superstructure rather than the MC phase as previously suggested. Intrinsic stacking faults in the sulfur sublattice and two different types of vacancy-ordering antiphase domains were also observed. Evidence from optical diffratograms of areas containing these defects suggests that complex features in the electron diffraction pattern may be artifactual.

The defects and intergrowth of lead oxides revealed by HRTEM

1992 ◽  
Vol 25 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Y. G. Wang ◽  
H. Q. Ye ◽  
K. H. Kuo ◽  
J. G. Guo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Structural Models ◽  
Planar Defects ◽  
Transmission Electron ◽  
Lead Oxides ◽  
Diffraction Patterns ◽  
Relationship Of

High-resolution transmission electron microscopy (HRTEM) and electron diffraction were used to investigate the microstructure of natural lead oxides found in Panzhihua Mountain, China. The electron diffraction patterns showed crossing of diffraction spots along 〈110〉 directions in litharge and along 〈100〉 directions in massicot and the structural images showed the domain-like texture, probably constructed by arrays of planar defects in the fundamental structures. Based upon the structure of these oxides the possible structural models of planar defects are discussed and the orientation relationship of litharge and massicot is determined.

Effects of High-Energy Ions on Synthetic Quartz

1972 ◽  
Vol 30 ◽  
pp. 544-545
Author(s):  
Joseph J. Comer ◽  
Charles Bergeron ◽  
Lester F. Lowe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Beam ◽  
High Energy ◽  
Transmission Electron ◽  
Kikuchi Lines ◽  
High Energy Ions ◽  
Diffraction Patterns ◽  
Dauphiné Twinning ◽  
Beam Damage

Using a Van De Graaff Accelerator thinned specimens were subjected to bombardment by 3 MeV N+ ions to fluences ranging from 4x1013 to 2x1016 ions/cm2. They were then examined by transmission electron microscopy and reflection electron diffraction using a 100 KV electron beam.At the lowest fluence of 4x1013 ions/cm2 diffraction patterns of the specimens contained Kikuchi lines which appeared somewhat broader and more diffuse than those obtained on unirradiated material. No damage could be detected by transmission electron microscopy in unannealed specimens. However, Dauphiné twinning was particularly pronounced after heating to 665°C for one hour and cooling to room temperature. The twins, seen in Fig. 1, were often less than .25 μm in size, smaller than those formed in unirradiated material and present in greater number. The results are in agreement with earlier observations on the effect of electron beam damage on Dauphiné twinning.

Examination of Extra Electron Diffraction Spots Observed in Deuterium-Irradiated Silicon by Using Parallel Electron Beam Illumination

1990 ◽  
Vol 48 (2) ◽  
pp. 490-491
Author(s):  
Ryuichiro Oshima ◽  
Shoichiro Honda ◽  
Tetsuo Tanabe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Silicon Single Crystal ◽  
Mixed Solution ◽  
Parallel Beam ◽  
Defect Clusters ◽  
Float Zone ◽  
Transmission Electron ◽  
Extra Electron ◽  
Diffraction Patterns

In order to examine the origin of extra diffraction spots and streaks observed in selected area diffraction patterns of deuterium irradiated silicon, systematic diffraction experiments have been carried out by using parallel beam illumination.Disc specimens 3mm in diameter and 0.5mm thick were prepared from a float zone silicon single crystal(B doped, 7kΩm), and were chemically thinned in a mixed solution of nitric acid and hydrogen fluoride to make a small hole at the center for transmission electron microscopy. The pre-thinned samples were irradiated with deuterium ions at temperatures between 300-673K at 20keV to a dose of 1022ions/m2, and induced lattice defects were examined under a JEOL 200CX electron microscope operated at 160kV.No indication of formation of amorphous was obtained in the present experiments. Figure 1 shows an example of defects induced by irradiation at 300K with a dose of 2xl021ions/m2. A large number of defect clusters are seen in the micrograph.

scholarly journals Identification of Faults in Asbestos Minerals and Application to Pollution Studies

1976 ◽  
Vol 34 ◽  
pp. 616-617
Author(s):  
K. Seshan ◽  
H.-R. Wenk
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Single Crystals ◽  
Twin Plane ◽  
Fibre Axis ◽  
Fibre Structure ◽  
Asbestos Fibre ◽  
Fibre Texture ◽  
Transmission Electron ◽  
Diffraction Patterns

Asbestos fibre texture occurs in various mineral groups (e.g. chrysotile, crocidolite, tremolite, grunerite, tourmaline) and it has been established that at least chrysotile is carcinogenic. We are investigating various aspects of the asbestos structure, with transmission electron microscopy (TEM) (1) in order to develop methods for unequivocal asbestos identification using minute samples and also to determine defects responsible for the fibre structure in these minerals which often occur as large, we 11-developed single crystals.In order to do this, we have started by investigating clinoamphibole asbestos such as tremolite Ca2Mg5[Si8O22] (OH, F)2 and crocidolite Na2 (Mg, Al, Fe3+, Fe2+) (Si8O22) (OH, F )2 , from California localities. In crocidoli te - asbestos we observed a high density of very narrow microtwins parallel to the fibre axis [001] (Fig. 1). They are often only 50-100Å wide. Diffraction patterns display the typical twin arrangement of spots and although preliminary contrast experiments are not yet conclusive the twin plane appears to be (100).

Dislocations and stacking faults in stainless steel

1957 ◽  
Vol 240 (1223) ◽  
pp. 524-538 ◽  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Grain Boundaries ◽  
Stacking Faults ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Thin Sections ◽  
Partial Dislocations ◽  
Transmission Electron

Further experiments by transmission electron microscopy on thin sections of stainless steel deformed by small amounts have enabled extended dislocations to be observed directly. The arrangement and motion of whole and partial dislocations have been followed in detail. Many of the dislocations are found to have piled up against grain boundaries. Other observations include the formation of wide stacking faults, the interaction of dislocations with twin boundaries, and the formation of dislocations at thin edges of the foils. An estimate is made of the stacking-fault energy from a consideration of the stresses present, and the properties of the dislocations are found to be in agreement with those expected from a metal of low stacking-fault energy.

scholarly journals High-resolution transmission electron microscopy on KHx–GIC's

1986 ◽  
Vol 1 (1) ◽  
pp. 177-186 ◽  
Author(s):  
L. Salamanca-Riba ◽  
N.-C. Yeh ◽  
M. S. Dresselhaus ◽  
M. Endo ◽  
T. Enoki
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Deuterium Content ◽  
X Ray Diffraction ◽  
High Hydrogen ◽  
Intermediate Phases ◽  
Transmission Electron ◽  
Final Compound ◽  
Lattice Images ◽  
Hydrogen Deuterium

The in-plane and c-axis structure of KHx—GIC's and KDy—GIC's is studied using transmission electron microscopy (TEM) and x-ray diffraction as a function of intercalation temperature and time. With the TEM, two commensurate in-plane phases are found to coexist in these compounds with relative concentrations depending on intercalation conditions. When the direct intercalation method is used, the first step of intercalation is the formation of a stage n potassium-GIC and the final compound is a stage n KHx—GIC (or KDy—GIC). Highresolution (00l) lattice images show direct evidence for intermediate phases in the intercalation process. These intermediate phases are hydrogen (deuterium) deficient and are found at the boundary between pure potassium regions and regions with high hydrogen (deuterium) content. A comparison of the structure for the two methods of intercalation of KH is also presented.

Defects in Germanium Nanocrystals Produced by Ion Implantation

2013 ◽  
Vol 709 ◽  
pp. 148-152
Author(s):  
Yu Juan Zhang ◽  
Lei Shang
Keyword(s):  
Electron Microscopy ◽  
Light Emission ◽  
Stacking Faults ◽  
Implantation Dose ◽  
Defect Structures ◽  
High Temperature Annealing ◽  
Planar Defects ◽  
Transmission Electron ◽  
Microstructural Defects ◽  
Germanium Nanocrystals

Germanium nanocrystals (Ge-nc) were produced by the implantation of Ge+ into a SiO2 film deposited on (100) Si, followed by a high-temperature annealing. High-resolution transmission electron microscopy (HRTEM) has been used to investigate the defect structures inside the Ge-nc produced by different implantation doses (1×1016, 2×1016, 4×1016 and 8×1016 cm-2). It has been found that the planar defects such as nanotwins and stacking faults (SFs) are dominant in Ge-nc (60%) for the samples with implantation doses higher than 2×1016 cm-2, while for the sample with an implantation dose lower than 1×1016 cm-2, fewer planar defects are observed in the Ge-nc (20%). The percentages of nanotwins in the planar defects are 87%, 77%, 67% and 60% in four samples, respectively. The twinning structures include single twins, double twins and multiple twins. We also found that there are only SFs in some nanocrystals, and in others the SFs coexist with twins. These microstructural defects are expected to play an important role in the light emission from the Ge-nc.

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