2026-09-21T23:07:33Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/45292 2023-07-11 col_2142_5131 col_2142_13836 com_2142_5130 com_2142_13835 com_2142_234

Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2013-05-24T22:02:27Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 1 Kim_KyouHyun.pdf: 4556380 bytes, checksum: 3dac9ee508db17f0bac12ef97b4d87d3 (MD5) Made available in DSpace on 2013-08-22T16:35:02Z (GMT). No. of bitstreams: 2 Kyou Hyun_Kim.pdf: 4559581 bytes, checksum: 01517235dc3fd2a0a7f5869a6c185d08 (MD5) license.txt: 4061 bytes, checksum: 583454f75f7b31b1d943bfdd8b7f1329 (MD5) Zuo, Jian-Min Zuo, Jian-Min Payne, David A. Dillon, Shen J. Martin, Lane W. Kim, Kyou Hyun 2013-08-22T16:35:02Z 2013-08-22T16:35:02Z 2013-08 2013-08-22T16:35:02Z 2013-08 Relaxor-ferroelectric single crystals, such as (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT), have the potential to transform technologies of medical imaging, actuation, and sensors, due to their extraordinary high piezoelectric effect. It has been suggested that polarization rotation driven by external electric fields is responsible for the large piezoelectric response. Polarization rotation is accompanied by a change in crystal symmetry and/or orientation. However, the nature of symmetry in PMN-xPT and other relaxor-ferroelectric crystals, despite extensive study by x-ray and neutron diffraction, is still controversial. Extensive studies have suggested the crystal symmetry varies on the nanoscopic scale and understanding the nature of local symmetry and its variations is thus critical to correlate the structure with polarization properties. In this thesis, the symmetry is measured based on the size of the crystal volume and the volume position in PMN-xPT single crystals. The study is enabled by the use of probes of different length scales to examine the symmetry of PMN-xPT single crystals. Local symmetry recorded by different probes is measured using quantitative convergent beam electron diffraction analysis (CBED) and transmission electron microscopy (TEM). Symmetry in CBED patterns is correlated with polarization direction with help of simulations. Furthermore, local symmetry fluctuation is observed using a new CBED method developed during this research. The technique enables the quantification of local symmetry development. http://hdl.handle.net/2142/45292 en Copyright 2013 Kyou Hyun Kim Piezoelectric Relaxor-ferroelectric single crystal Morphotropic phase boundary Symmetry Convergent beam electron diffraction Nanodomain structure Transmission Electron Microscopy (TEM) Local symmetry and polarization in relaxor-based ferroelectric crystals text Materials Science & Engineerng 1919 Materials Science & Engr 0130 University of Illinois at Urbana-Champaign Dissertation Ph.D. PHD:Materials Sci & Engr -UIUC 10KS0130PHD