{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/25415"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/25415","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Zero field NMR study on a spin glass: Iron-doped 2H-niobium diselenide","abstract":"We have used spin echoes to study the 93Nb NQR in 2H-NbSe2Fex. We measured (intensity)x(temperature), and T1P (spin-lattice relaxation parameter) and T2 (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x=O, 0.25%, 1% and 5%) and spin glass samples (x=8%, 10% and 12%). Defining the spin glass transition temperature Tg by the cusp of the susceptibility versus temperature curve, we find a well defined minima at T:Tg tn (intensity)x(temperature), T1P and T2 as a function of temperature. Deduction of a correlation time of Fe spins from T1P and T2 is complicated by the intensity changes which imply that 0ne observes different groups of nuclei at different temperatures. We propose a two-correlation-time model, which utilizes the anisotropy of the exchange interaction, to overcome this difficulty. All of our NQR results and the model calculation of the correlation times of Fe spins are best described by the phase transit ion picture of spin glasses.","abstract_html":"We have used spin echoes to study the 93Nb NQR in 2H-NbSe2Fex. We measured (intensity)x(temperature), and T1P (spin-lattice relaxation parameter) and T2 (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x=O, 0.25%, 1% and 5%) and spin glass samples (x=8%, 10% and 12%). Defining the spin glass transition temperature Tg by the cusp of the susceptibility versus temperature curve, we find a well defined minima at T:Tg tn (intensity)x(temperature), T1P and T2 as a function of temperature. Deduction of a correlation time of Fe spins from T1P and T2 is complicated by the intensity changes which imply that 0ne observes different groups of nuclei at different temperatures. We propose a two-correlation-time model, which utilizes the anisotropy of the exchange interaction, to overcome this difficulty. All of our NQR results and the model calculation of the correlation times of Fe spins are best described by the phase transit ion picture of spin glasses.","abstract_has_math":false,"creators":["Chen, Men-Chee"],"institution":null,"degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Physics","degree_department":null,"school":null,"contributors":["Slichter, C.P."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-06-16T13:54:59Z","date_published":"2011-06-16T13:54:59Z","updated_at":"2026-07-22T22:25:24Z","subjects":["zero field","Nuclear magnetic resonance (NMR)","spin glass","spin glass transition temperature","iron-doped 2H-niobium diselenide"],"languages":["en"],"rights":["1982 Men-Chee Chen"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["92639"],"render_values":[{"text":"92639","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/25415","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Slichter, C.P."]},{"key":"dc:creator","label":"Author","values":["Chen, Men-Chee"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-06-16T13:54:59Z","10000-01-01","1982"]},{"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":["zero field","Nuclear magnetic resonance (NMR)","spin glass","spin glass transition temperature","iron-doped 2H-niobium diselenide"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["1982 Men-Chee Chen"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["92639","http://hdl.handle.net/2142/25415"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["We have used spin echoes to study the 93Nb NQR in 2H-NbSe2Fex. We measured (intensity)x(temperature), and T1P (spin-lattice relaxation parameter) and T2 (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x=O, 0.25%, 1% and 5%) and spin glass samples (x=8%, 10% and 12%). Defining the spin glass transition temperature Tg by the cusp of the susceptibility versus temperature curve, we find a well defined minima at T:Tg tn (intensity)x(temperature), T1P and T2 as a function of temperature. Deduction of a correlation time of Fe spins from T1P and T2 is complicated by the intensity changes which imply that 0ne observes different groups of nuclei at different temperatures. We propose a two-correlation-time model, which utilizes the anisotropy of the exchange interaction, to overcome this difficulty. All of our NQR results and the model calculation of the correlation times of Fe spins are best described by the phase transit ion picture of spin glasses.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-16T13:54:58Z No. of bitstreams: 1 1982_chen.pdf: 3766545 bytes, checksum: 921a58036a6adb82c3eef7656cc8a69b (MD5)","Made available in DSpace on 2011-06-16T13:54:59Z (GMT). No. of bitstreams: 1 1982_chen.pdf: 3766545 bytes, checksum: 921a58036a6adb82c3eef7656cc8a69b (MD5) Previous issue date: 1982","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-16T13:54:59Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:13:01-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"]},{"key":"dc:title","label":"Title","values":["Zero field NMR study on a spin glass: Iron-doped 2H-niobium diselenide"]}]}],"canonical_facts":{"dc:contributor":["Slichter, C.P."],"dc:creator":["Chen, Men-Chee"],"dc:date":["2011-06-16T13:54:59Z","10000-01-01","1982"],"dc:description":["We have used spin echoes to study the 93Nb NQR in 2H-NbSe2Fex. We measured (intensity)x(temperature), and T1P (spin-lattice relaxation parameter) and T2 (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x=O, 0.25%, 1% and 5%) and spin glass samples (x=8%, 10% and 12%). Defining the spin glass transition temperature Tg by the cusp of the susceptibility versus temperature curve, we find a well defined minima at T:Tg tn (intensity)x(temperature), T1P and T2 as a function of temperature. Deduction of a correlation time of Fe spins from T1P and T2 is complicated by the intensity changes which imply that 0ne observes different groups of nuclei at different temperatures. We propose a two-correlation-time model, which utilizes the anisotropy of the exchange interaction, to overcome this difficulty. All of our NQR results and the model calculation of the correlation times of Fe spins are best described by the phase transit ion picture of spin glasses.","Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-16T13:54:58Z No. of bitstreams: 1 1982_chen.pdf: 3766545 bytes, checksum: 921a58036a6adb82c3eef7656cc8a69b (MD5)","Made available in DSpace on 2011-06-16T13:54:59Z (GMT). No. of bitstreams: 1 1982_chen.pdf: 3766545 bytes, checksum: 921a58036a6adb82c3eef7656cc8a69b (MD5) Previous issue date: 1982","Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Carolyn Mead (cmead2@illinois.edu) on 2011-06-16T13:54:59Z Item is restricted indefinitely.","Restriction data tranferred 2014-07-01T11:13:01-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: Thesis","Thesis","U of I Only"],"dc:identifier":["92639","http://hdl.handle.net/2142/25415"],"dc:language":["en"],"dc:rights":["1982 Men-Chee Chen"],"dc:subject":["zero field","Nuclear magnetic resonance (NMR)","spin glass","spin glass transition temperature","iron-doped 2H-niobium diselenide"],"dc:title":["Zero field NMR study on a spin glass: Iron-doped 2H-niobium diselenide"],"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"}