Structure and migration of planar defects in crystals observed in atomic scale

As was demonstrated by the present authors that atomic structure of simple crystal can be photographed by the conventional 100 kV electron microscope adjusted at “aberration free focus (AFF)” condition. In order to operate the microscope at AFF condition effectively, highly stabilized electron beams with small energy spread and small beam divergence are necessary. In the present observation, a 120 kV electron microscope with LaB6 electron gun was used. The most of the images were taken with the direct electron optical magnification of 1.3 million times and then magnified photographically.1. Twist boundary of ZnSFig. 1 is the image of wurtzite single crystal with twist boundary grown on the surface of zinc crystal by the reaction of sulphur vapour of 1540 Torr at 500°C. Crystal surface is parallel to (00.1) plane and electron beam is incident along the axis normal to the crystal surface. In the twist boundary there is a dislocation net work between two perfect crystals with a certain rotation angle.

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New Aspects in the Design of Electron Optical Magnification Systems

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009628x ◽

1972 ◽

Vol 30 ◽

pp. 606-607

Author(s):

Willem H.J. Andersen

Keyword(s):

Electron Microscope ◽

Imaging System ◽

Chromatic Aberration ◽

Research Tool ◽

Energy Losses ◽

Objective Lens ◽

Theoretical Limit ◽

Optical Magnification ◽

Chromatic Aberrations ◽

High Degree

Electron microscope design, and particularly the design of the imaging system, has reached a high degree of perfection. Present objective lenses perform up to their theoretical limit, while the whole imaging system, consisting of three or four lenses, provides very wide ranges of magnification and diffraction camera length with virtually no distortion of the image. Evolution of the electron microscope in to a routine research tool in which objects of steadily increasing thickness are investigated, has made it necessary for the designer to pay special attention to the chromatic aberrations of the magnification system (as distinct from the chromatic aberration of the objective lens). These chromatic aberrations cause edge un-sharpness of the image due to electrons which have suffered energy losses in the object.There exist two kinds of chromatic aberration of the magnification system; the chromatic change of magnification, characterized by the coefficient Cm, and the chromatic change of rotation given by Cp.

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A New High Intensity Grid Cap for RCA-EMU-3 Electron Microscopes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101323 ◽

1968 ◽

Vol 26 ◽

pp. 316-317

Author(s):

George Christov ◽

Bolivar J. Lloyd

Keyword(s):

Electron Beam ◽

Electron Microscope ◽

High Voltage ◽

High Intensity ◽

Electron Gun ◽

Tungsten Filament ◽

Fluorescent Screen ◽

Electron Microscopes ◽

Pass Through ◽

Ground Potential

A new high intensity grid cap has been designed for the RCA-EMU-3 electron microscope. Various parameters of the new grid cap were investigated to determine its characteristics. The increase in illumination produced provides ease of focusing on the fluorescent screen at magnifications from 1500 to 50,000 times using an accelerating voltage of 50 KV.The EMU-3 type electron gun assembly consists of a V-shaped tungsten filament for a cathode with a thin metal threaded cathode shield and an anode with a central aperture to permit the beam to course the length of the column. The cathode shield is negatively biased at a potential of several hundred volts with respect to the filament. The electron beam is formed by electrons emitted from the tip of the filament which pass through an aperture of 0.1 inch diameter in the cap and then it is accelerated by the negative high voltage through a 0.625 inch diameter aperture in the anode which is at ground potential.

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Images and Applications of Ion Explosion Spike Pits

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100181683 ◽

1990 ◽

Vol 48 (1) ◽

pp. 584-585

Author(s):

P. Fraundorf ◽

J. Tentschert

Keyword(s):

Electron Microscope ◽

Transmission Electron Microscope ◽

Bulk Material ◽

Coulomb Repulsion ◽

The Body ◽

Atomic Scale ◽

Early Solar System ◽

Transmission Electron ◽

Nuclear Particle ◽

Particle Tracks

Since the discovery of their etchability in the early 1960‘s, nuclear particle tracks in insulators have had a diverse and exciting history of application to problems ranging from the selective filtration of cancer cells from blood to the detection of 244Pu in the early solar system. Their usefulness stems from the fact that they are comprised of a very thin (e.g. 20-40Å) damage core which etches more rapidly than does the bulk material. In fact, because in many insulators tracks are subject to radiolysis damage (beam annealing) in the transmission electron microscope, the body of knowledge concerning etched tracks far outweighs that associated with latent (unetched) tracks in the transmission electron microscope.With the development of scanned probe microscopies with lateral resolutions on the near atomic scale, a closer look at the structure of unetched nuclear particle tracks, particularly at their point of interface with solid surfaces, is now warranted and we think possible. The ion explosion spike model of track formation, described loosely, suggests that a burst of ionization along the path of a charged particle in an insulator creates an electrostatically unstable array of adjacent ions which eject one another by Coulomb repulsion from substitutional into interstitial sites. Regardless of the mechanism, the ejection process which acts to displace atoms along the track core seems likely to operate at track entry and exit surfaces, with the added feature of mass loss at those surfaces as well. In other words, we predict pits whose size is comparable to the track core width.

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The buckling of thin EM specimens

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100177386 ◽

1990 ◽

Vol 48 (4) ◽

pp. 850-851

Author(s):

A.R. Thölén

Keyword(s):

Electron Microscope ◽

Elastic Properties ◽

Crystal Surface ◽

Specimen Surface ◽

Radius Of Curvature ◽

Thin Foils ◽

Thin Electron ◽

Regular Patterns

Thin electron microscope specimens often contain irregular bend contours (Figs. 1-3). Very regular bend patterns have, however, been observed around holes in some ion-milled specimens. The purpose of this investigation is twofold. Firstly, to find the geometry of bent specimens and the elastic properties of extremely thin foils and secondly, to obtain more information about the background to the observed regular patterns.The specimen surface is described by z = f(x,y,p), where p is a parameter, eg. the radius of curvature of a sphere. The beam is entering along the z—direction, which coincides with the foil normal, FN, of the undisturbed crystal surface (z = 0). We have here used FN = [001]. Furthermore some low indexed reflections are chosen around the pole FN and in our fcc crystal the following g-vectors are selected:

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Redox-driven atomic-scale changes in mixed catalysts: VOX/WOX/α-TiO2 (110)

RSC Advances ◽

10.1039/c4ra14140g ◽

2014 ◽

Vol 4 (110) ◽

pp. 64608-64616 ◽

Cited By ~ 5

Author(s):

Z. Feng ◽

M. E. McBriarty ◽

A. U. Mane ◽

J. Lu ◽

P. C. Stair ◽

...

Keyword(s):

Single Crystal ◽

Crystal Surface ◽

Oxide Catalysts ◽

Atomic Scale ◽

Redox Behavior ◽

Single Crystal Surface ◽

Tungsten Oxides ◽

Mixed Monolayer ◽

X Ray

X-ray study of vanadium–tungsten mixed-monolayer-oxide catalysts grown on the rutile α-TiO2 (110) single crystal surface shows redox behavior not observed for lone supported vanadium or tungsten oxides.

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Atomic-scale structure and non-stoichiometry of meteoritic hibonite: a transmission electron microscope study

American Mineralogist ◽

10.2138/am-2022-8014 ◽

2021 ◽

Keyword(s):

Electron Microscope ◽

Transmission Electron Microscope ◽

Microscope Study ◽

Electron Microscope Study ◽

Scale Structure ◽

Atomic Scale ◽

Transmission Electron ◽

Transmission Electron Microscope Study ◽

Atomic Scale Structure

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FEI Titan 80-300 TEM

Journal of large-scale research facilities JLSRF ◽

10.17815/jlsrf-2-66 ◽

2016 ◽

Vol 2 ◽

Cited By ~ 36

Author(s):

Andreas Thust ◽

Juri Barthel ◽

Karsten Tillmann

Keyword(s):

Electron Microscope ◽

Solid State ◽

Spherical Aberration ◽

Atomic Scale ◽

Atomic Resolution ◽

Lens System ◽

Stage Design ◽

Precise Positioning ◽

Transmission Electron ◽

Wide Range

The FEI Titan 80-300 TEM is a high-resolution transmission electron microscope equipped with a field emission gun and a corrector for the spherical aberration (CS) of the imaging lens system. The instrument is designed for the investigation of a wide range of solid state phenomena taking place on the atomic scale, which requires true atomic resolution capabilities. Under optimum optical settings of the image CS-corrector (CEOS CETCOR) the point-resolution is extended up to the information limit of well below 100 pm with 200 keV and 300 keV electrons. A special piezo-stage design allows ultra-precise positioning of the specimen in all 3 dimensions. Digital images are acquired with a Gatan 2k x 2k slow-scan charged coupled device camera.

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