Hrem Investigation of Ai-MgO Interface

1993 ◽  
Vol 319 ◽  
Author(s):  
W.P. Vellinga ◽  
M. Verwerft ◽  
J.Th.M. De Hosson ◽  
Tj. Hibma
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Metal Ceramic ◽  
Mgo Substrate ◽  
Image Simulations

AbstractA metal-ceramic interface was produced by depositing Al on a {100} MgO substrate in a MBE system. The interface was studied with High Resolution Electron Microscopy. Results of some image simulations are shown, raising the question if effects of ionicity and charging should be taken into account.

Atomic chemistry by HREM and image simulations?

1986 ◽  
Vol 44 ◽  
pp. 828-829
Author(s):  
J.M. Howe ◽  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Image Simulations

The technique of high-resolution electron microscopy (HREM) is invaluable to the materials scientist because it allows examination of microstructural features at levels of resolution that are unobtainable by most other methods. Although the structural information which can be determined by HREM and accompanying image simulations has been well documented in the literature, there have only been a few cases where this technique has been used to reveal the chemistry of individual columns or planes of atoms, as occur in segregated and ordered materials.

High resolution electron microscopy of bismuth and thallium superconductors

1988 ◽  
Vol 46 ◽  
pp. 868-869
Author(s):  
J. P. Zhang ◽  
D. J. Li ◽  
H. Shibahara ◽  
L. D. Marks
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Shear Wave ◽  
High Resolution Electron Microscopy ◽  
Double Layers ◽  
Resolution Electron ◽  
New Frontier ◽  
Image Simulations

A new frontier has opened up in the field of superconductivity with the very recent discovery of compounds of bismuth and thallium which appear to superconduct above 100 K. Both of these compounds appear to be perovskite derivatives with intergrowth of the basic perovskite with bismuth double-layers and perhaps thallium double layers. The structure of these compounds, however, is not as yet completely established, particularly the thallium material which to date has only been produced in very small quantities due to the toxic nature of thallium.We have very recently been studying both the bismuth and thallium superconductors by high resolution electron microscopy. The bismuth material appears to be an intergrowth of a five layer perovskite with a buckling of the structure along the b axis (see Figure 1) which preliminary image simulations suggest is in the form of a shear wave of amplitude in the region of 0.25 Angstroms.

High-Resolution Electron Microscopy of Dislocation Cores in NiAl

1998 ◽  
Vol 552 ◽  
Author(s):  
D. Stöckle ◽  
W. Sigle ◽  
A. Seeger
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Peierls Stress ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Stress Components ◽  
Vector Distribution ◽  
Image Simulations ◽  
High Resolution Electron Micrographs

ABSTRACTThe atomic structure of dislocation cores in NiAl is studied by high-resolution transmission electron microscopy (HRTEM) and molecular dynamics (MD) calculations. Results are presented on dislocations with Burgers vectors b=a<100> and a<111>. A comparison with HRTEM image simulations indicates that the core of a 45° a <100> dislocation consists of Al atoms. The Burgers vector distribution shows a width of 2.2b. This corresponds very closely to MD results and is consistent with the relatively low Peierls stress of this dislocation. By detailed image analysis the angular dependence of the shear stress components of the dislocation are made visible. MD results obtained from 45° dislocations with opposite screw components suggest, that the helicity of the screw component might be discernible from high-resolution electron micrographs. A a<111> dislocation with <110> line direction is shown which exhibits a rather wide dissociation, probably into two a/2<111> partials.

High-resolution electron microscopy of dislocations of MgO

1994 ◽  
Vol 9 (11) ◽  
pp. 2953-2958 ◽  
Author(s):  
J. Ohta ◽  
K. Suzuki ◽  
T. Suzuki
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Resolution ◽  
Ion Irradiation ◽  
High Resolution Electron Microscopy ◽  
Burgers Vector ◽  
Resolution Electron ◽  
Lattice Images ◽  
Simulated Images ◽  
Image Simulations

Dislocations in MgO introduced by ion irradiation and by plastic deformation are observed by HREM. Depending on the Burgers vector and the dislocation character, various types of lattice images are obtained. Image simulations are performed for the inclination of dislocations, as well as for dissociated dislocations. A comparison of observed and simulated images shows that inclination of nondissociated dislocations makes them appear as if they were dissociated; in reality a/2(110) dislocations in MgO are not dissociated.

scholarly journals Comparisons Of Observed And Simulated Atomic Structures Of Pd/NiO Heterophase Interfaces

1992 ◽  
Vol 295 ◽  
Author(s):  
M. I. Buckett ◽  
J. P. Shaffer ◽  
Karl L. Merkle
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Rigid Body ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Boundary Plane ◽  
Misfit Dislocations ◽  
Atomic Structures ◽  
Resolution Electron ◽  
Image Simulations

AbstractHigh-resolution electron microscopy (HREM) and image simulations using the multislice algorithm have been used to study the atomic structure of a Pd/NiO (111) interface in an intemally oxidized sample. Samples prepared in this way result in cube-on-cube oriented or twin-related precipitates whose (111) interfaces exhibit a contrast modulation along the boundary plane in HREM images. Previous studies have reported that the observed structural period of this modulation corresponds qualitatively to the expected spacing if the boundary was composed of a network of misfit dislocations. In this study, rigid models of the (111) interface as viewed from the [110] direction were simulated using the EMS suite of programs. The questions we address are: (1) whether the terminating plane on the oxide side is made up of a Ni or an 0 layer, and (2) whether a rigid body translation normal to the interface exists. Finally, the results of the simulations are compared and contrasted to through-focal experimental images to investigate the origin of the contrast modulations and their possible relation to the extent of the misfit localization in these systems.

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