{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/19256"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/19256","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"New perspectives of pure and lanthanum modified lead zirconate titanate crystalline solutions","abstract":"Two types of oxygen octahedral rotational systems (R- and M-type) were found in the rhombohedral phase field of lead zirconate titanate (PZT). A hierarchy of domain structure was observed in the high temperature rhombohedral ferroelectric (FE) state, where local octahedral tilt domains on the scale of $\\sim$50 A existed within the normal FE micron-sized domains. Constriction of the polarization by the local oxygen octahedral tilting was found. Small amounts of La- and Nb-doping was found to relax the lattice, resulting in normal square dielectric hysteresis loops.","abstract_html":"Two types of oxygen octahedral rotational systems (R- and M-type) were found in the rhombohedral phase field of lead zirconate titanate (PZT). A hierarchy of domain structure was observed in the high temperature rhombohedral ferroelectric (FE) state, where local octahedral tilt domains on the scale of $\\sim$50 A existed within the normal FE micron-sized domains. Constriction of the polarization by the local oxygen octahedral tilting was found. Small amounts of La- and Nb-doping was found to relax the lattice, resulting in normal square dielectric hysteresis loops.","abstract_has_math":true,"creators":["Dai, Xunhu"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science and Engineering","degree_department":null,"school":null,"contributors":["Viehland, Dwight D."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-05-07T12:01:52Z","date_published":"2011-05-07T12:01:52Z","updated_at":"2026-07-22T22:25:12Z","subjects":["Engineering, Materials Science"],"languages":["eng"],"rights":["Copyright 1995 Dai, Xunhu"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9624330","(UMI)AAI9624330"],"render_values":[{"text":"AAI9624330","href":null,"code":true},{"text":"(UMI)AAI9624330","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/19256","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Viehland, Dwight D."]},{"key":"dc:creator","label":"Author","values":["Dai, Xunhu"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-05-07T12:01:52Z","10000-01-01","1995"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science and Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Engineering, Materials Science"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 1995 Dai, Xunhu"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["AAI9624330","(UMI)AAI9624330","http://hdl.handle.net/2142/19256"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Two types of oxygen octahedral rotational systems (R- and M-type) were found in the rhombohedral phase field of lead zirconate titanate (PZT). A hierarchy of domain structure was observed in the high temperature rhombohedral ferroelectric (FE) state, where local octahedral tilt domains on the scale of $\\sim$50 A existed within the normal FE micron-sized domains. Constriction of the polarization by the local oxygen octahedral tilting was found. Small amounts of La- and Nb-doping was found to relax the lattice, resulting in normal square dielectric hysteresis loops.","Incorporation of La into PZT (PLZT) was found to disrupt long-range FE order. Near the antiferroelectric (AFE-FE) phase boundary within the high-Zr phase region of PZT, an incommensurate antiferroelectric (AFE$\\sb{\\rm In}$) state was found to develop at the expense of the FE phase upon La-modification. In addition, evidence of a relaxor state with antipolar order was found in high La-content rhombohedral PLZT, which was characterized by relaxor-like dielectric behavior and double P-E loop features. For PZT compositions away from the AFE-FE phase boundary and far into the rhombohedral and tetragonal FE phase regions, La-modification was observed to transform the normal micron-sized FE domain structure into nanodomain state, which exhibited typical relaxor behavior. In the tetragonal phase field, spontaneous (thermally driven) relaxor-normal ferroelectric transformations were observed near crossover compositions between normal and relaxor states.","Finally, it was shown that an increase in the ease of polarization switching is essential for maximum electrically-induced strains in PLZT ceramics. For PLZT compositions close to the morphotropic phase boundary (MPB), this was realized by adjusting the base composition to be close to the boundary between tetragonal and rhombohedral states, where the polarization has maximum equivalent orientations by which to switch. For PLZT compositions locating in either the rhombohedral or tetragonal states, the ease of polarization switching was facilitated by La-doping until the point where the normal micron-sized ferroelectric domains began to break up into tweed-like subdomain structures. Polarization switching may then occur through the subdomain state, rather than by the creation and subsequent motion of normal micron-sized domain boundaries.","Made available in DSpace on 2011-05-07T12:01:52Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9624330.pdf: 10111105 bytes, checksum: c95d918d65e59c85d434fe09f8666e18 (MD5) Previous issue date: 1995","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:35:43Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:14:11-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"]},{"key":"dc:title","label":"Title","values":["New perspectives of pure and lanthanum modified lead zirconate titanate crystalline solutions"]}]}],"canonical_facts":{"dc:contributor":["Viehland, Dwight D."],"dc:creator":["Dai, Xunhu"],"dc:date":["2011-05-07T12:01:52Z","10000-01-01","1995"],"dc:description":["Two types of oxygen octahedral rotational systems (R- and M-type) were found in the rhombohedral phase field of lead zirconate titanate (PZT). A hierarchy of domain structure was observed in the high temperature rhombohedral ferroelectric (FE) state, where local octahedral tilt domains on the scale of $\\sim$50 A existed within the normal FE micron-sized domains. Constriction of the polarization by the local oxygen octahedral tilting was found. Small amounts of La- and Nb-doping was found to relax the lattice, resulting in normal square dielectric hysteresis loops.","Incorporation of La into PZT (PLZT) was found to disrupt long-range FE order. Near the antiferroelectric (AFE-FE) phase boundary within the high-Zr phase region of PZT, an incommensurate antiferroelectric (AFE$\\sb{\\rm In}$) state was found to develop at the expense of the FE phase upon La-modification. In addition, evidence of a relaxor state with antipolar order was found in high La-content rhombohedral PLZT, which was characterized by relaxor-like dielectric behavior and double P-E loop features. For PZT compositions away from the AFE-FE phase boundary and far into the rhombohedral and tetragonal FE phase regions, La-modification was observed to transform the normal micron-sized FE domain structure into nanodomain state, which exhibited typical relaxor behavior. In the tetragonal phase field, spontaneous (thermally driven) relaxor-normal ferroelectric transformations were observed near crossover compositions between normal and relaxor states.","Finally, it was shown that an increase in the ease of polarization switching is essential for maximum electrically-induced strains in PLZT ceramics. For PLZT compositions close to the morphotropic phase boundary (MPB), this was realized by adjusting the base composition to be close to the boundary between tetragonal and rhombohedral states, where the polarization has maximum equivalent orientations by which to switch. For PLZT compositions locating in either the rhombohedral or tetragonal states, the ease of polarization switching was facilitated by La-doping until the point where the normal micron-sized ferroelectric domains began to break up into tweed-like subdomain structures. Polarization switching may then occur through the subdomain state, rather than by the creation and subsequent motion of normal micron-sized domain boundaries.","Made available in DSpace on 2011-05-07T12:01:52Z (GMT). No. of bitstreams: 2 license.txt: 4922 bytes, checksum: 910b249b4beec47e7ab768910c8f966f (MD5) 9624330.pdf: 10111105 bytes, checksum: c95d918d65e59c85d434fe09f8666e18 (MD5) Previous issue date: 1995","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding (hding2@illinois.edu) on 2011-05-07T14:35:43Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:14:11-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: ETDs are only available to UIUC Users without author permission","ETDs are only available to UIUC Users without author permission","U of I Only"],"dc:identifier":["AAI9624330","(UMI)AAI9624330","http://hdl.handle.net/2142/19256"],"dc:language":["eng"],"dc:rights":["Copyright 1995 Dai, Xunhu"],"dc:subject":["Engineering, Materials Science"],"dc:title":["New perspectives of pure and lanthanum modified lead zirconate titanate crystalline solutions"],"dc:type":["text"],"thesis:degree_discipline":["Materials Science and Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:12Z"}