Regensburg 2019 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 29: Microscopy, Tomography and Spectroscopy with X-ray Photons, Electrons, Ions and Positrons (joint session KFM/HL)
HL 29.4: Vortrag
Mittwoch, 3. April 2019, 10:30–10:50, H47
Investigation of superlattice defects in magnetite mesocrystals via (S)TEM tomography — •Sebastian Sturm1, Daniel Wolf1, Julian Brunner2, Elena Sturm2, Axel Lubk1, and Bernd Büchner1 — 1IFW Dresden, Deutschland — 2FB Chemie, Universität Konstanz, Deutschland
Mesocrystals are a special sub class of colloidal crystals fulfilling the definition of a crystal on two different hierarchical levels, exhibiting single crystal like diffraction pattern in small angles as well as single or texture like pattern in wide angles. They are thus formed by assembly of single crystalline building blocks in a long range ordered superlattice with reoccurring specific crystallographic orientation of the crystalline building blocks. In order to characterize the growth mechanism and investigate the defect structure of 3D iron oxide self-assembled mesocrystaline materials, we employed electron tomography on specifically picked areas. This allows to resolve structural defects generated within the superlattice during the self-assembly process inside the crystal in three dimensions. In case of a mesocrystal with fcc superlattice, grown by dislocation driven crystal growth mechanism, the disintegration of a (111) plane intersecting screw dislocation defect structure, in two Shockley-partials has been resolved, very similar to traditional fcc crystals. The aim is to study the structure of these partials and relate it to the elastic properties of the mesocrystal.