Special Seminar: Nadezda V. Tarakina, Characterisation of structural defects in layered compounds using transmission electron microscopy and X-ray diffraction
Date: Wed 21 May 2014, 14:00 - 15:00
Location: The People’s Palace (PP2)
The presence of defects in materials, such as dislocations, grain boundaries, stacking faults, twins, etc. is usually considered undesirable. However, such imperfections not always influence negatively on materials’ properties. A careful analysis of microstructural features can provide detailed insights into structure-property relationships, and even stimulate the engineering of defects on purpose. In this talk I will present two different cases where defects play opposite roles. First I will discuss Bi2Se3 topological-insulator thin films. The presence of structural defects in such films negatively affects their transport properties. Through a detailed microstructural characterisation using TEM and X-ray diffraction one can not only reveal the origin of different defects, but also propose a mechanism for suppressing them. Then I will address complex MO(OH)2 oxyhydroxides (M = Ti,Hf,Zr), which possess high concentrations of structural defects. The presence of defects not only positively influences the sorption properties of these compounds but generally also enhances their stability. I will show how the crystal structures of these compounds have been solved using mainly X-ray powder diffraction data.
Dr. Nadezda Tarakina
Institute of Physics
University of Würzburg