Filters

2017 - 20202

More filters

2021 - 20232
Reset filters

Settings

Publisher: Copenhagen : Munksgaard × WGL Institute: PDI ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Scanning X-ray nanodiffraction from ferroelectric domains in strained K0.75Na0.25NbO3 epitaxial films grown on (110) TbScO3
    (Copenhagen : Munksgaard, 2017) Schmidbauer, Martin; Hanke, Michael; Kwasniewski, Albert; Braun, Dorothee; von Helden, Leonard; Feldt, Christoph; Leake, Steven John; Schwarzkopf, Jutta
    Scanning X-ray nanodiffraction on a highly periodic ferroelectric domain pattern of a strained K0.75Na0.25NbO3 epitaxial layer has been performed by using a focused X-ray beam of about 100 14;nm probe size. A 90°-rotated domain variant which is aligned along [1 2]TSO has been found in addition to the predominant domain variant where the domains are aligned along the [12]TSO direction of the underlying (110) TbScO3 (TSO) orthorhombic substrate. Owing to the larger elastic strain energy density, the 90°-rotated domains appear with significantly reduced probability. Furthermore, the 90°-rotated variant shows a larger vertical lattice spacing than the 0°-rotated domain variant. Calculations based on linear elasticity theory substantiate that this difference is caused by the elastic anisotropy of the K0.75Na0.25NbO3 epitaxial layer.
  • Thumbnail Image
    Item
    X-ray diffraction reveals the amount of strain and homogeneity of extremely bent single nanowires
    (Copenhagen : Munksgaard, 2020) Davtyan, Arman; Kriegner, Dominik; Holý, Václav; AlHassan, Ali; Lewis, Ryan B.; McDermott, Spencer; Geelhaar, Lutz; Bahrami, Danial; Anjum, Taseer; Ren, Zhe; Richter, Carsten; Novikov, Dmitri; Müller, Julian; Butz, Benjamin; Pietsch, Ullrich
    Core-shell nanowires (NWs) with asymmetric shells allow for strain engineering of NW properties because of the bending resulting from the lattice mismatch between core and shell material. The bending of NWs can be readily observed by electron microscopy. Using X-ray diffraction analysis with a micro- and nano-focused beam, the bending radii found by the microscopic investigations are confirmed and the strain in the NW core is analyzed. For that purpose, a kinematical diffraction theory for highly bent crystals is developed. The homogeneity of the bending and strain is studied along the growth axis of the NWs, and it is found that the lower parts, i.e. close to the substrate/wire interface, are bent less than the parts further up. Extreme bending radii down to ∼3 μm resulting in strain variation of ∼2.5% in the NW core are found. © 2020.