Research Fellows Directory
Dr Alexander Eggeman
University of Manchester
Electron diffraction is an extremely powerful technique for studying materials at length scales ranging from individual atoms, through to macroscopic crystalline grains. We can use magnetic fields to focus an electron beam to a diameter less than one nanometre, while the electron wavelength can be made small enough to allow scattering from individual atomic columns, meaning that electron diffraction can be used to study nanoscale variations in atomic structure, elemental composition and atomic disorder from a variety of materials.
With advances in computer controlled experiments it is possible to generate vast amounts of diffraction data from volumes of material, however there is the need to develop new methods to isolate the unique structural signal from individual features within the complex microstructure. Through statistical methods I am developing approaches to extract information at both the atomic and microstructural length scales from single experiments, allowing the complete 3D structural relationships between grains, secondary phases and defects to be measured. This can provide insight to the mechanical behaviour of materials for thermal coatings through to engine components, or help explain the electrical or optical properties of nanoscale devices.
My other interest is in studying disorder in materials through electron diffraction. Interpreting and quantifying this signal from experimental data can be difficult, requiring models comprising tens of thousands of atoms to accurately describe the disordered state of a material. Parallel processing on commercial graphics cards (built for video gaming) has proved a powerful and cost effective method to tackle these problems.