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Full-Text Articles in Physics
Crystallite Phase And Orientation Determinations Of (Mn, Ga) As/Gaas-Crystallites Using Analyzed (Precession) Electron Diffraction Patterns, Ines Häusler, Stavros Nicolopoulos, Edgar F. Rauch, K. Volz, Peter Moeck
Crystallite Phase And Orientation Determinations Of (Mn, Ga) As/Gaas-Crystallites Using Analyzed (Precession) Electron Diffraction Patterns, Ines Häusler, Stavros Nicolopoulos, Edgar F. Rauch, K. Volz, Peter Moeck
Physics Faculty Publications and Presentations
Outline of the presentation:
1. Material system: (Mn,Ga)As/GaAs-crystallites
2. Structure analysis using Nano-beam Diffraction (NBD) Precession Electron Diffraction Technique (PED) --> Structure type I + II
3. Phase and orientation mapping using ASTAR
4. Conclusion
Precession Electron Diffraction And Its Advantages For Structural Fingerprinting In The Transmission Electron Microscope, Peter Moeck, Sergei Rouvimov
Precession Electron Diffraction And Its Advantages For Structural Fingerprinting In The Transmission Electron Microscope, Peter Moeck, Sergei Rouvimov
Physics Faculty Publications and Presentations
The foundations of precession electron diffraction in a transmission electron microscope are outlined. A brief illustration of the fact that laboratory-based powder X-ray diffraction fingerprinting is not feasible for nanocrystals is given. A procedure for structural fingerprinting of nanocrystals on the basis of structural data that can be extracted from precession electron diffraction spot patterns is proposed.
Structural Identification Of Cubic Iron-Oxide Nanocrystal Mixtures: X-Ray Powder Diffraction Versus Quasi-Kinematic Transmission Electron Microscopy, Peter Moeck
Physics Faculty Publications and Presentations
Two novel (and proprietary) strategies for the structural identification of a nanocrystal from either a single high-resolution (HR) transmission electron microscopy (TEM) image or a single precession electron diffraction pattern are proposed and their advantages discussed in comparison to structural fingerprinting from powder X-ray diffraction patterns. Simulations for cubic magnetite and maghemite nanocrystals are used as examples.
A Transmission Electron Microscope For Lecture Demonstrations, J. A. Panitz, Gertrude Rempfer
A Transmission Electron Microscope For Lecture Demonstrations, J. A. Panitz, Gertrude Rempfer
Physics Faculty Publications and Presentations
A simple transmission electron microscope (TEM) suitable for lecture demonstrations is described. In this TEM electrons are created in a glow discharge between two parallel electrodes in air at a reduced pressure. The electrons are collimated by a small hole in theanode, focused by a solenoid that acts as an electromagnetic lens, and imaged on a thin layer of phosphor deposited inside an Erlenmeyer flask. An image of a biological sample placed between the source and the lens can be magnified about 20 times. The microscope uses inexpensive components that can be quickly assembled during a demonstration. The TEMprovides a …
Transmission Electron Goniometry And Its Relation To Electron Tomography For Materials Science Apoplications, Peter Moeck, P. Fraundorf
Transmission Electron Goniometry And Its Relation To Electron Tomography For Materials Science Apoplications, Peter Moeck, P. Fraundorf
Physics Faculty Publications and Presentations
Aspects of transmission electron goniometry are discussed. Combined with high resolution phase contrast transmission electron microscopy (HRTEM) and atomic resolution scanning TEM (STEM) in the atomic number contrast (Z-STEM) or the phase contrast bright field mode, transmission electron goniometry offers the opportunity to develop dedicated methods for the crystallographic characterization of nanocrystals in three dimensions. The relationship between transmission electron goniometry and electron tomography for materials science applications is briefly discussed. Internet based java applets that facilitate the application of transmission electron goniometry for cubic crystals with calibrated tilt-rotation and double-tilt specimen holders/goniometers are mentioned. The so called cubic-minimalistic tilt …
Making Sense Of Nanocrystal Lattice Fringes, P. Fraundorf, Wentao Qin, Peter Moeck, Eric Mandell
Making Sense Of Nanocrystal Lattice Fringes, P. Fraundorf, Wentao Qin, Peter Moeck, Eric Mandell
Physics Faculty Publications and Presentations
The orientation dependence of thin-crystal lattice fringes can be gracefully quantified using fringe-visibility maps, a direct-space analog of Kikuchi maps [Nishikawa and Kikuchi, Nature (London) 121, 1019 (1928)]. As in navigation of reciprocal space with the aid of Kikuchi lines, fringe-visibility maps facilitate acquisition of crystallographic information from lattice images. In particular, these maps can help researchers to determine the three-dimensional lattice of individual nanocrystals, to 'fringe-fingerprint' collections of randomly oriented particles, and to measure local specimen thickness with only a modest tilt. Since the number of fringes in an image increases with maximum spatial-frequency squared, these strategies (with help …