Microdiffraction from out of Phase Domain Boundaries and Stacking Faults

It has been pointed out1 that any discontinuity at the edge of a crystal or within a crystal may give rise to spot splitting in microdiffraction patterns.The present work gives the basic theory for an antiphase domain boundary in Cu3Au and a twinning boundary in a f.c.c. crystal illuminated by a finite electron beam, which has a diameter of about 15Å. The treatment is based on the weak phase object approximation. These boundaries are planar faults. Multiplying a step function s(x) by the crystal potential expresses the discontinuity in the potential of the sample. When both sides of the boundary in the sample are illuminated by the finite coherent source and the boundary is parallel to the electron beam, the splitting of microdiffraction spots results from the convolution of the Fourier transform of the step function and the finite coherent source function.

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STUDY ON THE PEIREL–NABARRO STRESS OF IRON ALUMINIDES

Surface Review and Letters ◽

10.1142/s0218625x12500576 ◽

2012 ◽

Vol 19 (06) ◽

pp. 1250057 ◽

Cited By ~ 1

Author(s):

L. X. PANG ◽

N. F. HAN ◽

H. SHI ◽

J. XU ◽

X. H. HAO ◽

...

Keyword(s):

Domain Boundary ◽

Antiphase Domain ◽

Iron Aluminides ◽

Stress Model ◽

Theoretical Yield ◽

Domain Boundaries ◽

Ordered Intermetallic ◽

Critical Resolved Shear Stress ◽

B2 Structure ◽

Type Crystal

The modified Peirel–Nabarro model of dislocations is not valid for the superdislocation bounded by the antiphase domain boundaries in long-range ordered intermetallic. In this work, a new Peirel–Nabarro Stress model is developed to take into account the critical resolved shear stress of antiphase domain boundary (APDB). Based on it, the Peirel–Nabarro Stress of DO3 structure and B2 structure in iron aluminides are calculated. Comparing the Peirel–Nabarro Stress of dislocations and the crystal theoretical yield strength, the results demonstrate B2-type crystal has good plasticity. It coincides with the experimental results well.

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Electron beam-induced current imaging of antiphase domain boundaries in heteroepitaxial GaAs on group IV semiconductors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176861 ◽

1990 ◽

Vol 48 (4) ◽

pp. 746-747

Author(s):

D.P. Malta ◽

J.B. Posthill ◽

R. Venkatasubramanian ◽

M.L. Timmons ◽

T.P. Humphreys ◽

...

Keyword(s):

Electron Beam ◽

Defect Density ◽

High Mobility ◽

Antiphase Domain ◽

Group Iv ◽

Induced Current ◽

Bulk Gaas ◽

Group Iv Semiconductors ◽

Domain Boundaries ◽

Electron Beam Induced Current

A viable GaAs heteroepitaxy technology is desirable in order to exploit the high mobility and direct band gap properties of GaAs while avoiding the high cost, defect density, and weight of bulk GaAs. Microstructural defects such as dislocations, microtwins, and stacking faults found in most heteroepitaxial GaAs films have thus far inhibited the achievement of device quality films. In addition, the formation of antiphase domain boundaries (APBs), at which As-As bonds and Ga-Ga bonds exist, is undesirable because they are electrically active. The APBs are believed to form due to the presence of single atomic steps on the underlying group IV substrate. Transmission electron microscopy investigations have previously reported the presence of APBs in GaAs heteroepitaxial films. Since the APBs act as electron-hole recombination sites, the electron beam-induced current. (EBIC) imaging mode of the scanning electron microscope (SEM) is ideally suited for straightforward and statistically significant. GaAs heteroepitaxial film evaluation.

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Electron beam induced current and cathodoluminescence imaging of the antiphase domain boundaries in GaAs grown on Si

Applied Physics Letters ◽

10.1063/1.102790 ◽

1990 ◽

Vol 56 (4) ◽

pp. 376-378 ◽

Cited By ~ 9

Author(s):

K. Nauka ◽

G. A. Reid ◽

Z. Liliental‐Weber

Keyword(s):

Electron Beam ◽

Antiphase Domain ◽

Induced Current ◽

Domain Boundaries ◽

Electron Beam Induced Current ◽

Cathodoluminescence Imaging

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Brownian Motion and Coarsening of Domain Boundaries on (7×7)-Si(111)

MRS Proceedings ◽

10.1557/proc-404-117 ◽

1995 ◽

Vol 404 ◽

Cited By ~ 1

Author(s):

Pita Atala ◽

R. J. Phaneuf ◽

N. C. Barteltl ◽

W. Swiech ◽

E. Bauer

Keyword(s):

Average Distance ◽

Domain Boundary ◽

Statistical Problem ◽

Low Energy ◽

One Dimension ◽

Phase Domain ◽

Time Motion ◽

Domain Boundaries ◽

Low Energy Electron ◽

Energetic Interactions

AbstractWe have used low-energy electron microscopy to investigate the real-time motion of (7×7) out-of-phase domain boundaries in the (7×7) reconstruction on vicinal Si(111), just below the phase transition temperature. As a function of time, the domain boundaries wander and coalesce in one-dimension, parallel to the step edges. We have established that the motion is consistent with the statistical problem of a random walk in the presence of absorbing barriers and have measured the diffusion coefficient for domain boundary wandering. The average distance between domain boundaries becomes large as they coarsen, consequently energetic interactions are not significant in determining their arrangement on this surface.

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Domain Formation in Synthetic Quartz

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064839 ◽

1971 ◽

Vol 29 ◽

pp. 156-157

Author(s):

Joseph J. Comer

Keyword(s):

Electron Beam ◽

Room Temperature ◽

Domain Formation ◽

Synthetic Quartz ◽

Transmission Electron ◽

Black Spots ◽

Diffraction Mode ◽

Domain Boundaries ◽

Kikuchi Lines ◽

Straight Lines

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.

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Nucleation of Disorder in Fe3Al Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061574 ◽

1967 ◽

Vol 25 ◽

pp. 312-313

Author(s):

P. R. Swann ◽

W. R. Duff ◽

R. M. Fisher

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Annealing Temperature ◽

Antiphase Domain ◽

Effect Of Temperature ◽

Domain Structures ◽

Transmission Electron ◽

Domain Boundaries ◽

Higher Temperature ◽

The One

Recently we have investigated the phase equilibria and antiphase domain structures of Fe-Al alloys containing from 18 to 50 at.% Al by transmission electron microscopy and Mössbauer techniques. This study has revealed that none of the published phase diagrams are correct, although the one proposed by Rimlinger agrees most closely with our results to be published separately. In this paper observations by transmission electron microscopy relating to the nucleation of disorder in Fe-24% Al will be described. Figure 1 shows the structure after heating this alloy to 776.6°C and quenching. The white areas are B2 micro-domains corresponding to regions of disorder which form at the annealing temperature and re-order during the quench. By examining specimens heated in a temperature gradient of 2°C/cm it is possible to determine the effect of temperature on the disordering reaction very precisely. It was found that disorder begins at existing antiphase domain boundaries but that at a slightly higher temperature (1°C) it also occurs by homogeneous nucleation within the domains. A small (∼ .01°C) further increase in temperature caused these micro-domains to completely fill the specimen.

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Antiphase Boundaries in Ordered Ni3FE Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006221x ◽

1969 ◽

Vol 27 ◽

pp. 62-63

Author(s):

Y. H. Liu

Keyword(s):

Domain Size ◽

Antiphase Domain ◽

X Ray Diffraction ◽

X Ray ◽

Hardening Mechanism ◽

Superlattice Structure ◽

Disordered Phase ◽

Domain Boundaries ◽

Atomic Scattering ◽

The Difference

Ordered Ni3Fe crystals possess a LI2 type superlattice similar to the Cu3Au structure. The difference in slip behavior of the superlattice as compared with that of a disordered phase has been well established. Cottrell first postulated that the increase in resistance for slip in the superlattice structure is attributed to the presence of antiphase domain boundaries. Following Cottrell's domain hardening mechanism, numerous workers have proposed other refined models also involving the presence of domain boundaries. Using the anomalous X-ray diffraction technique, Davies and Stoloff have shown that the hardness of the Ni3Fe superlattice varies with the domain size. So far, no direct observation of antiphase domain boundaries in Ni3Fe has been reported. Because the atomic scattering factors of the elements in NijFe are so close, the superlattice reflections are not easily detected. Furthermore, the domain configurations in NioFe are thought to be independent of the crystallographic orientations.

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The observation of solutions in Ni3Nb

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104765 ◽

1988 ◽

Vol 46 ◽

pp. 540-541

Author(s):

Z.M. Wang ◽

J.P. Zhang

Keyword(s):

Electron Microscopy ◽

High Resolution ◽

Phase Modulation ◽

High Resolution Electron Microscopy ◽

Antiphase Domain ◽

Boundary Area ◽

Matrix Type ◽

Resolution Electron ◽

Domain Boundaries ◽

Kontorova Model

High resolution electron microscopy reveals that antiphase domain boundaries in β-Ni3Nb have a hexagonal unit cell with lattice parameters ah=aβ and ch=bβ, where aβ and bβ are of the orthogonal β matrix. (See Figure 1.) Some of these boundaries can creep “upstairs” leaving an incoherent area, as shown in region P. When the stepped boundaries meet each other, they do not lose their own character. Our consideration in this work is to estimate the influnce of the natural misfit δ{(ab-aβ)/aβ≠0}. Defining the displacement field at the boundary as a phase modulation Φ(x), following the Frenkel-Kontorova model [2], we consider the boundary area to be made up of a two unit chain, the upper portion of which can move and the lower portion of the β matrix type, assumed to be fixed. (See the schematic pattern in Figure 2(a)).

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