Search Results

You are looking at 1 - 10 of 10 items :

  • "Exit wave reconstruction" x
Clear All

Exit wave reconstruction from focal series of HRTEM images, single crystal XRD and total energy studies on SbxWO3þy (x 0.11) Miia KlingstedtI, Margareta Sundberg*, I, Lars ErikssonI, Sarah HaighII,III, Angus KirklandII, Daniel GrünerIV, Annick De BackerV, Sandra Van AertV and Osamu Terasaki*, I, VI I Department of Materials and Environmental Chemistry, Stockholm University, 106 91, Stockholm, Sweden II Department of Materials, University of Oxford, Parks Road, Oxford, OX1 3PH U.K. III Now at The University of Manchester, Materials Science Centre, Grosvenor

-Lincoln, Lincoln, NE 68588-0650, USA Received June 28, 2002; accepted July 27, 2002 Abstract. A series of structure analyses during 1994– 2001 by electron crystallographic techniques applied to phases in aluminum alloys are reviewed. Methods for structure solution employ electron diffraction intensity data collected by the precession technique, by selected area mi- cro-diffraction and by the convergent-beam technique. High-resolution electron microscope images (HRTEM) are treated by a different kind of processing, including exit wave reconstruction. Crystallographic calculations

FT q(r)ϕ(r) Q(H) I FTQ(H)W(H) I (r)ψ(r) Fig. 1. Schematic diagram showing the image formation process. resolution of electron microscope by image processing. Apart from the trial-and-error method, different methods of solving the inverse problem in HREM without relying on the prior knowledge and proposed models for the exam- ined structure have been developed. They can be grouped into two types. One way is to divide the task into two parts corresponding to electron optics and crystallography, re- spectively. The first part is the exit wave reconstruction, which

× 50 nm3 (corresponding to about 283 600 unit cells of YAG). Exit wave reconstruction (EWR) and iterative image simulation procedure. High-resolution phase-contrast focal series and exit wave reconstruction combined with image simulation were used to gain information on the orientation of the two crystals with respect to each other (Fig. 2). A rotation of 36.9° around the common <100> direction (Fig. 2d) of the bicrystal is read directly from the diffraction pat- tern. To minimize beam irradiation damage, convergent beam diffraction analysis was avoided: the

bronzes Acta Crystallogr. A 1976 32 551 [24] M. Klingstedt, M. Sundberg, L. Eriksson, S. Haigh, A. Kirkland, D. Grüner, A. De Backer, S. Van Aert, O. Terasaki, Exit wave reconstruction from focal series of HRTEM images, single crystal XRD and total energy studies on Sb x WO 3+ y ( x ~0.11). Z. Krist-Cryst. Mater. 2012 , 227 , 341. Klingstedt M Sundberg M Eriksson L Haigh S Kirkland A Grüner D De Backer A Van Aert S Terasaki O Exit wave reconstruction from focal series of HRTEM images, single crystal XRD and total energy studies on Sb x WO 3+ y ( x ~0.11). Z. Krist

high-resolution images Aside from local strain measurements, atomic-resolution micrographs also allow for assessing the local symmetry of individual unit cells and thus for indirectly measuring the local polarization of the sample (see DOI: 10.1515/PSR.2019.0015). The ferroelectric polarization can be determined from the atomic displacements measured in atomic resolution images. Earlier reports on polarization mapping mostly used HRTEM techniques such as negative spherical aberration (Cs) condition [ 131 ] or exit wave reconstruction of focal series [ 74 ]. However

left), octaeders (Fig. 1 right) cub- octaeders, and spheres. Fig. 1: Wet-chemically prepared 8 nm FePt3 nanocubes (left) and 5.6 nm gas-phase-synthesized icosaeder FePt nanoparticle These differently shaped nanocrystals were analysed by high-resolution transmission electron microscopy. The layer and atom column resolved crystal structure was determined for selected nanoparticles by newly developed exit wave reconstruction techniques. Results In Fig. 2 a typical high resolution image (phase contrast after exit wave reconstruction) of an colloidal 3 nm spherical

3D volume are indexed and their intensities extracted for ab-initio structure solution. Disorder and distortion or intergrown phases are simulated using the DISCUS software package[5] through accurate analysis of the structure’s variance. The results are confirmed by Rietveld Methods[6] and comparison to TEM holograms[7] reconstructed from focal series. Zeolite Beta[8] was chosen as a test sample. The structures of a polymorphic mixture of Zeolite Beta A and B was solved ab-initio from a single ADT dataset. The disorder type was identified by exit wave