**Are you an EPFL student looking for a semester project?**

Work with us on data science and visualisation projects, and deploy your project as an app on top of GraphSearch.

Lecture# Electron Diffraction: Basics & Applications

Description

This lecture introduces the fundamentals of electron diffraction, covering topics such as Bragg's law, reciprocal lattice, multiple beam scattering, and dynamical scattering. It explains the origin of contrast in TEM images, the importance of electron diffraction in crystallography, and the applications of electron diffraction in material analysis. By the end of the lecture, students should understand why certain particles appear darker than others, the significance of oscillatory contrast, and the principles behind bright-field and dark-field imaging techniques.

Official source

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

In course

MSE-352: Introduction to microscopy + Laboratory work

Ce cours d'introduction à la microscopie a pour but de donner un apperçu des différentes techniques d'analyse de la microstructure et de la composition des matériaux, en particulier celles liées aux m

Related concepts (180)

Instructors (2)

Crystal structure

In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions, or molecules in a crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns that repeat along the principal directions of three-dimensional space in matter. The smallest group of particles in the material that constitutes this repeating pattern is the unit cell of the structure.

Reciprocal lattice

In physics, the reciprocal lattice represents the Fourier transform of another lattice. The direct lattice or real lattice is a periodic function in physical space, such as a crystal system (usually a Bravais lattice). The reciprocal lattice exists in the mathematical space of spatial frequencies, known as reciprocal space or k space, where refers to the wavevector. In quantum physics, reciprocal space is closely related to momentum space according to the proportionality , where is the momentum vector and is the reduced Planck constant.

Diffraction

Diffraction is the interference or bending of waves around the corners of an obstacle or through an aperture into the region of geometrical shadow of the obstacle/aperture. The diffracting object or aperture effectively becomes a secondary source of the propagating wave. Italian scientist Francesco Maria Grimaldi coined the word diffraction and was the first to record accurate observations of the phenomenon in 1660.

Powder diffraction

Powder diffraction is a scientific technique using X-ray, neutron, or electron diffraction on powder or microcrystalline samples for structural characterization of materials. An instrument dedicated to performing such powder measurements is called a powder diffractometer. Powder diffraction stands in contrast to single crystal diffraction techniques, which work best with a single, well-ordered crystal. Diffraction grating The most common type of powder diffraction is with x-rays, the focus of this article although some aspects of neutron powder diffraction are mentioned.

Electron diffraction

Electron diffraction refers to changes in the direction of electron beams due to interactions with atoms. Close to the atoms the changes are described as Fresnel diffraction; far away they are called Fraunhofer diffraction. The resulting map of the directions of the electrons far from the sample (Fraunhofer diffraction) is called a diffraction pattern, see for instance Figure 1. These patterns are similar to x-ray and neutron diffraction patterns, and are used to study the atomic structure of gases, liquids, surfaces and bulk solids.

Related lectures (94)

Electron Diffraction: Basics & ApplicationsMSE-352: Introduction to microscopy + Laboratory work

Explores electron diffraction basics, including Bragg's law, reciprocal lattice, and applications like crystal phase discrimination.

Deviation from Bragg scattering

Covers electron diffraction theory, Bragg's law, reciprocal lattice, Ewald sphere, and weak-beam dark-field imaging.

Electron Diffraction: Basics and Applications

Covers the fundamentals of electron diffraction and its applications in understanding crystal structures and symmetry, including lattice vectors, lattice planes, and dark-field imaging techniques.

Electron Diffraction: Basics & ApplicationsMSE-352: Introduction to microscopy + Laboratory work

Explores electron diffraction fundamentals, crystal symmetry, and advanced techniques for materials analysis.

Reciprocal Lattice and Diffraction

Explores reciprocal lattice in 2D systems, diffraction from lattice and atomic structures, emphasizing scattering and constructive interference.