{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25094"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25094","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Electron spin-lattice relaxation in YB3+ - doped silicate glass","abstract":"\"Relaxation rates of Yb3+ ions incorporated in low concentrations into a host silicate glass have been measured using a pulse saturation/recovery technique at 9.5 GHz over the temperature range 1.5-7.0 K. Compared with similar measurements made on crystalline material, the temperature dependence of the recovery rates for the two-phonon Raman process is anomalously weak (T6 instead of T9). This anomaly suggests the need to modify the Debye density of states. Fractal models have been suggested for the thermal properties of glasses and for similarly anomalous spin relaxation behavior in proteins. An alternate model is proposed here that is supported by other measurements of low temperature thermal transport properties in glasses. The relaxation rates are interpreted in terms of a \"\"thermally effective\"\" density of states consisting of only low frequency extended vibrational modes. This is smaller than the total density of vibrational modes (extended and localized) measured, for example, by neutron scattering. An estimate for the localization frequency or crossover frequency between these two regimes can be extracted from fits to the lowest concentration data.\"","abstract_html":""Relaxation rates of Yb3+ ions incorporated in low concentrations into a host silicate glass have been measured using a pulse saturation/recovery technique at 9.5 GHz over the temperature range 1.5-7.0 K. Compared with similar measurements made on crystalline material, the temperature dependence of the recovery rates for the two-phonon Raman process is anomalously weak (T6 instead of T9). This anomaly suggests the need to modify the Debye density of states. Fractal models have been suggested for the thermal properties of glasses and for similarly anomalous spin relaxation behavior in proteins. An alternate model is proposed here that is supported by other measurements of low temperature thermal transport properties in glasses. The relaxation rates are interpreted in terms of a ""thermally effective"" density of states consisting of only low frequency extended vibrational modes. This is smaller than the total density of vibrational modes (extended and localized) measured, for example, by neutron scattering. An estimate for the localization frequency or crossover frequency between these two regimes can be extracted from fits to the lowest concentration data."","abstract_has_math":false,"creators":["Stevens, Sally Beth"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Stapleton, H.J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-06-01T14:26:41Z","date_published":"2011-06-01T14:26:41Z","updated_at":"2026-07-22T22:25:24Z","subjects":["YB3+-doped silicate glass","pulse saturation/recovery technique","electron spin-lattice relaxation"],"languages":["en"],"rights":["1990 Sally Beth Stevens"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["3480342"],"render_values":[{"text":"3480342","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25094","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Stapleton, H.J."]},{"key":"dc:creator","label":"Author","values":["Stevens, Sally Beth"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-06-01T14:26:41Z","10000-01-01","1990"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation / Thesis","text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Physics"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["YB3+-doped silicate glass","pulse saturation/recovery technique","electron spin-lattice relaxation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1990 Sally Beth Stevens"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["3480342","http://hdl.handle.net/2142/25094"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["\"Relaxation rates of Yb3+ ions incorporated in low concentrations into a host silicate glass have been measured using a pulse saturation/recovery technique at 9.5 GHz over the temperature range 1.5-7.0 K. Compared with similar measurements made on crystalline material, the temperature dependence of the recovery rates for the two-phonon Raman process is anomalously weak (T6 instead of T9). This anomaly suggests the need to modify the Debye density of states. Fractal models have been suggested for the thermal properties of glasses and for similarly anomalous spin relaxation behavior in proteins. An alternate model is proposed here that is supported by other measurements of low temperature thermal transport properties in glasses. The relaxation rates are interpreted in terms of a \"\"thermally effective\"\" density of states consisting of only low frequency extended vibrational modes. This is smaller than the total density of vibrational modes (extended and localized) measured, for example, by neutron scattering. An estimate for the localization frequency or crossover frequency between these two regimes can be extracted from fits to the lowest concentration data.\"","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-01T14:26:40Z No. of bitstreams: 1 1990_stevens.pdf: 3044372 bytes, checksum: 4ac7e9e5fc73672c54d72c4b19680f6c (MD5)","Made available in DSpace on 2011-06-01T14:26:41Z (GMT). No. of bitstreams: 1 1990_stevens.pdf: 3044372 bytes, checksum: 4ac7e9e5fc73672c54d72c4b19680f6c (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-01T14:26:41Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:11:33-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Electron spin-lattice relaxation in YB3+ - doped silicate glass"]}]}],"canonical_facts":{"dc:contributor":["Stapleton, H.J."],"dc:creator":["Stevens, Sally Beth"],"dc:date":["2011-06-01T14:26:41Z","10000-01-01","1990"],"dc:description":["\"Relaxation rates of Yb3+ ions incorporated in low concentrations into a host silicate glass have been measured using a pulse saturation/recovery technique at 9.5 GHz over the temperature range 1.5-7.0 K. Compared with similar measurements made on crystalline material, the temperature dependence of the recovery rates for the two-phonon Raman process is anomalously weak (T6 instead of T9). This anomaly suggests the need to modify the Debye density of states. Fractal models have been suggested for the thermal properties of glasses and for similarly anomalous spin relaxation behavior in proteins. An alternate model is proposed here that is supported by other measurements of low temperature thermal transport properties in glasses. The relaxation rates are interpreted in terms of a \"\"thermally effective\"\" density of states consisting of only low frequency extended vibrational modes. This is smaller than the total density of vibrational modes (extended and localized) measured, for example, by neutron scattering. An estimate for the localization frequency or crossover frequency between these two regimes can be extracted from fits to the lowest concentration data.\"","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-01T14:26:40Z No. of bitstreams: 1 1990_stevens.pdf: 3044372 bytes, checksum: 4ac7e9e5fc73672c54d72c4b19680f6c (MD5)","Made available in DSpace on 2011-06-01T14:26:41Z (GMT). No. of bitstreams: 1 1990_stevens.pdf: 3044372 bytes, checksum: 4ac7e9e5fc73672c54d72c4b19680f6c (MD5) Previous issue date: 1990","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-01T14:26:41Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:11:33-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["3480342","http://hdl.handle.net/2142/25094"],"dc:language":["en"],"dc:rights":["1990 Sally Beth Stevens"],"dc:subject":["YB3+-doped silicate glass","pulse saturation/recovery technique","electron spin-lattice relaxation"],"dc:title":["Electron spin-lattice relaxation in YB3+ - doped silicate glass"],"dc:type":["Dissertation / Thesis","text"],"thesis:degree_discipline":["Physics"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."]},"updated_at":"2026-07-22T22:25:24Z"}