{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/82882"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/82882","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Radiation-Enhanced Diffusion and Defect Production During Ion Irradiation of MgO and Al(2)O(3)","abstract":"Radiation enhanced diffusion of O$\\sp{18}$, Ca and Zn buried tracer layers in MBE grown MgO was measured following irradiation with either 2.0 MeV Kr or 1.0 MeV Ne, He or H from 30 to 1500$\\sp\\circ$C. This represents the first reported RED measurements on an oxide system. Ion beam mixing at 30$\\sp\\circ$C on both sublattices was approximately 1.0 to 5.0 A$\\sp5$/ev indicating the temperature independent mixing (ballistic mixing) is produced only by direct recoil and cascade events and that thermal spikes are not significant. D$\\sb{\\rm red}$ was proportional to the square root of the irradiation flux with an activation enthalpy of 1.2 eV for diffusion on the anion sublattice from 1350 to 1500$\\sp\\circ$C. The flux dependence is characteristic of kinetics in the recombination limited regime; accordingly, the measured activation enthalpy of 1.2 eV is identified as one-half the migration enthalpy of the anion vacancy. This assignment agrees with the predicted anion vacancy migration enthalpy of 2.1 to 2.4 eV. Between 1150$\\sp\\circ$C and 1350$\\sp\\circ$C an apparent activation enthalpy of 4.1 eV was measured. This enthalpy was attributed to vacancy clustering reactions. Measurements on the cation sublattice were conducted at temperatures below 900$\\sp\\circ$C. At higher temperatures excessive thermal diffusion from extrinsic vacancies stemming from trivalent impurities prevented measurements of RED.","abstract_html":"Radiation enhanced diffusion of O$\\sp{18}$, Ca and Zn buried tracer layers in MBE grown MgO was measured following irradiation with either 2.0 MeV Kr or 1.0 MeV Ne, He or H from 30 to 1500$\\sp\\circ$C. This represents the first reported RED measurements on an oxide system. Ion beam mixing at 30$\\sp\\circ$C on both sublattices was approximately 1.0 to 5.0 A$\\sp5$/ev indicating the temperature independent mixing (ballistic mixing) is produced only by direct recoil and cascade events and that thermal spikes are not significant. D$\\sb{\\rm red}$ was proportional to the square root of the irradiation flux with an activation enthalpy of 1.2 eV for diffusion on the anion sublattice from 1350 to 1500$\\sp\\circ$C. The flux dependence is characteristic of kinetics in the recombination limited regime; accordingly, the measured activation enthalpy of 1.2 eV is identified as one-half the migration enthalpy of the anion vacancy. This assignment agrees with the predicted anion vacancy migration enthalpy of 2.1 to 2.4 eV. Between 1150$\\sp\\circ$C and 1350$\\sp\\circ$C an apparent activation enthalpy of 4.1 eV was measured. This enthalpy was attributed to vacancy clustering reactions. Measurements on the cation sublattice were conducted at temperatures below 900$\\sp\\circ$C. At higher temperatures excessive thermal diffusion from extrinsic vacancies stemming from trivalent impurities prevented measurements of RED.","abstract_has_math":true,"creators":["Van Sambeek, Andrew I."],"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":["Averback, R.S."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-09-25T20:53:28Z","date_published":"2015-09-25T20:53:28Z","updated_at":"2026-07-22T22:26:20Z","subjects":["Physics, Radiation"],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(MiAaPQ)AAI9737278"],"render_values":[{"text":"(MiAaPQ)AAI9737278","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/82882","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Averback, R.S."]},{"key":"dc:creator","label":"Author","values":["Van Sambeek, Andrew I."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-09-25T20:53:28Z","10000-01-01","1997"]},{"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":["Physics, Radiation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/82882","(MiAaPQ)AAI9737278"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Radiation enhanced diffusion of O$\\sp{18}$, Ca and Zn buried tracer layers in MBE grown MgO was measured following irradiation with either 2.0 MeV Kr or 1.0 MeV Ne, He or H from 30 to 1500$\\sp\\circ$C. This represents the first reported RED measurements on an oxide system. Ion beam mixing at 30$\\sp\\circ$C on both sublattices was approximately 1.0 to 5.0 A$\\sp5$/ev indicating the temperature independent mixing (ballistic mixing) is produced only by direct recoil and cascade events and that thermal spikes are not significant. D$\\sb{\\rm red}$ was proportional to the square root of the irradiation flux with an activation enthalpy of 1.2 eV for diffusion on the anion sublattice from 1350 to 1500$\\sp\\circ$C. The flux dependence is characteristic of kinetics in the recombination limited regime; accordingly, the measured activation enthalpy of 1.2 eV is identified as one-half the migration enthalpy of the anion vacancy. This assignment agrees with the predicted anion vacancy migration enthalpy of 2.1 to 2.4 eV. Between 1150$\\sp\\circ$C and 1350$\\sp\\circ$C an apparent activation enthalpy of 4.1 eV was measured. This enthalpy was attributed to vacancy clustering reactions. Measurements on the cation sublattice were conducted at temperatures below 900$\\sp\\circ$C. At higher temperatures excessive thermal diffusion from extrinsic vacancies stemming from trivalent impurities prevented measurements of RED.","Made available in DSpace on 2015-09-25T20:53:28Z (GMT). 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This represents the first reported RED measurements on an oxide system. Ion beam mixing at 30$\\sp\\circ$C on both sublattices was approximately 1.0 to 5.0 A$\\sp5$/ev indicating the temperature independent mixing (ballistic mixing) is produced only by direct recoil and cascade events and that thermal spikes are not significant. D$\\sb{\\rm red}$ was proportional to the square root of the irradiation flux with an activation enthalpy of 1.2 eV for diffusion on the anion sublattice from 1350 to 1500$\\sp\\circ$C. The flux dependence is characteristic of kinetics in the recombination limited regime; accordingly, the measured activation enthalpy of 1.2 eV is identified as one-half the migration enthalpy of the anion vacancy. This assignment agrees with the predicted anion vacancy migration enthalpy of 2.1 to 2.4 eV. Between 1150$\\sp\\circ$C and 1350$\\sp\\circ$C an apparent activation enthalpy of 4.1 eV was measured. This enthalpy was attributed to vacancy clustering reactions. Measurements on the cation sublattice were conducted at temperatures below 900$\\sp\\circ$C. At higher temperatures excessive thermal diffusion from extrinsic vacancies stemming from trivalent impurities prevented measurements of RED.","Made available in DSpace on 2015-09-25T20:53:28Z (GMT). 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