{"id":{"repo_id":"nus","oai_identifier":"oai:scholarbank.nus.edu.sg:10635/27646"},"canonical_url":"https://search.dev.ndltd.org/etd/nus/oai:scholarbank.nus.edu.sg:10635/27646","repository":{"repo_id":"nus","name":"National University of Singapore","base_url":"https://scholarbank.nus.edu.sg/oai/request"},"display":{"title":"Brillouin scattering investigation of nanomagnetic structures","abstract":"Brillouin light scattering is employed to study the dynamical properties of arrays of vertical ferromagnetic nanowires and nanorings, which show great promise as high-density magnetic storage and sensor devices. Three closely related projects are reported: (1) observation of bulk magnon quantization in Ni nanowires: bulk spin wave quantization has been observed, and the magnon frequencies are found to decrease with increasing wire diameter. (2) investigation into the magnetic interaction between FeCo nanowires in closely-packed arrays: conclusive evidence of collective spin waves arising from the dipolar coupling which is manifested as a reduction in spin wave frequency with decreasing interwire spacing is found, and (3) study of the spin dynamics of large-aspect-ratio Ni nanorings: spin dynamics of high-aspect-ratio Ni nanorings is found to compare well with macroscopic theory. Micromagnetic simulations show that, for low applied magnetic fields, the nanorings undergo a transition from a b bamboob to b twisted bamboob magnetic state.","abstract_html":"Brillouin light scattering is employed to study the dynamical properties of arrays of vertical ferromagnetic nanowires and nanorings, which show great promise as high-density magnetic storage and sensor devices. Three closely related projects are reported: (1) observation of bulk magnon quantization in Ni nanowires: bulk spin wave quantization has been observed, and the magnon frequencies are found to decrease with increasing wire diameter. (2) investigation into the magnetic interaction between FeCo nanowires in closely-packed arrays: conclusive evidence of collective spin waves arising from the dipolar coupling which is manifested as a reduction in spin wave frequency with decreasing interwire spacing is found, and (3) study of the spin dynamics of large-aspect-ratio Ni nanorings: spin dynamics of high-aspect-ratio Ni nanorings is found to compare well with macroscopic theory. Micromagnetic simulations show that, for low applied magnetic fields, the nanorings undergo a transition from a b bamboob to b twisted bamboob magnetic state.","abstract_has_math":false,"creators":["WANG ZHIKUI"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2008,"date_issued":"2008-08-11","date_published":"2008-08-11","updated_at":"2026-07-24T03:32:18Z","subjects":["Spin dynamics, nanostructure, Brillouin Light scattering, spin waves, nanomagnetism, ferromagnetism"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["WANG ZHIKUI"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2008-08-11"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://scholarbank.nus.edu.sg/handle/10635/27646"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Spin dynamics, nanostructure, Brillouin Light scattering, spin waves, nanomagnetism, ferromagnetism"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://scholarbank.nus.edu.sg/bitstreams/2996943d-4bf5-4771-a497-4f9603cf6fe2/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Brillouin light scattering is employed to study the dynamical properties of arrays of vertical ferromagnetic nanowires and nanorings, which show great promise as high-density magnetic storage and sensor devices. Three closely related projects are reported: (1) observation of bulk magnon quantization in Ni nanowires: bulk spin wave quantization has been observed, and the magnon frequencies are found to decrease with increasing wire diameter. (2) investigation into the magnetic interaction between FeCo nanowires in closely-packed arrays: conclusive evidence of collective spin waves arising from the dipolar coupling which is manifested as a reduction in spin wave frequency with decreasing interwire spacing is found, and (3) study of the spin dynamics of large-aspect-ratio Ni nanorings: spin dynamics of high-aspect-ratio Ni nanorings is found to compare well with macroscopic theory. 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(2) investigation into the magnetic interaction between FeCo nanowires in closely-packed arrays: conclusive evidence of collective spin waves arising from the dipolar coupling which is manifested as a reduction in spin wave frequency with decreasing interwire spacing is found, and (3) study of the spin dynamics of large-aspect-ratio Ni nanorings: spin dynamics of high-aspect-ratio Ni nanorings is found to compare well with macroscopic theory. 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