{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/129895"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/129895","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Spin-torque-driven magnetization dynamics for neuromorphic functionality","abstract":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms","abstract_html":"Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms","abstract_has_math":false,"creators":["Klause, Robin"],"institution":"University of Illinois Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science & Engr","degree_department":null,"school":null,"contributors":["Hoffmann, Axel F.","Hoffmann, Axel F","Cahill, David G","Zuo, Jian-Min","Rakheja, Shaloo"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2025,"date_issued":"2025-05-19","date_published":"2025-05-19","updated_at":"2026-07-22T22:25:06Z","subjects":["Spintronics","Magnetic This Films","Spin-orbit Torques","Magnetization Dynamics"],"languages":["en","eng"],"rights":["Copyright 2025 Robin Klause"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/129895","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Hoffmann, Axel F.","Hoffmann, Axel F","Cahill, David G","Zuo, Jian-Min","Rakheja, Shaloo"]},{"key":"dc:creator","label":"Author","values":["Klause, Robin"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2025-05-19","2025-08"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science & Engr"]},{"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 Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Spintronics","Magnetic This Films","Spin-orbit Torques","Magnetization Dynamics"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2025 Robin Klause"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/129895"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms","The student, Robin Klause, accepted the attached license on 2025-05-08 at 09:00.","The student, Robin Klause, submitted this Dissertation for approval on 2025-05-08 at 09:14.","This Dissertation was approved for publication on 2025-05-19 at 13:28.","DSpace SAF Submission Ingestion Package generated from Vireo submission #22128 on 2025-10-20 at 20:14:40","With the ever-increasing demand for computationally demanding tasks and large scale memory, new information processing and storage technology is needed. Spintronics plays a key role in the development of faster, smaller, and more energy efficient technology. In this work, the focus lies on the electrical control of magnetization dynamics through spin-orbit torques and the exploration of their potential for enabling neuromorphic functionality. More specifically, unconventional spin-orbit torques and the coupling of spin-Hall nano-oscillators are explored. First, unconventional spin-orbit torque generation in the non-collinear antiferromagnet and altermagnet Mn$_3$Pt is explored. The thin film growth process is optimized based on the structural characterization, and the electrical transport properties. Spin-torque ferromagnetic-resonance reveals that unconventional spin-orbit torques, resulting from a spin polarization component along the current direction, are generated when current is applied along specific directions with respect to the crystal and magnetic order. Second, unconventional spin-orbit torque generation in CrPt$_3$ is studied. Spin-torque ferromagnetic-resonance and second harmonic Hall measurements of CrPt$_3$/Cu/Ni$_{81}$Fe$_{19}$ heterostructures reveal that unconventional field-like spin-orbit torques are generated in both ferrimagnetic and paramagnetic CrPt$_3$ films indicating that the magnetic ordering does not play a role in generating unconventional torques. Instead, numerical calculations reveal that the unconventional torques stem from indirect non-local spin-orbit torques and symmetry breaking at the CrPt$_3$/Cu interface. Third, micromagnetic simulations show that unconventional spin-orbit torques can be used to generate magnetic droplet solitons in a ferromagnet with perpendicular magnetic anisotropy without applying an in-plane magnetic field. Due to the non-local injection of spin-orbit torques, which differs from the typical spin-valve geometry, multiple magnetic droplets can be generated and annihilated using specific current pulses. Last, Pt/Ni$_{81}$Fe$_{19}$ spin-Hall nano-oscillators are fabricated on Si substrate. Injection-locking of the oscillations to an {\\em rf} signal reveal that direct electrical coupling of two oscillators is unfeasible due to the low power generation of a spin-Hall nano-oscillator. However, the frequency behavior of two connected oscillators can be tuned using two voltage sources. In addition, a fabrication process for Pt/Ni$_{81}$Fe$_{19}$ oscillators on top of an Y$_3$Fe$_5$O$_{12}$ film that were grown on Gd$_3$Ga$_5$O$_{12}$ is developed. This is non-trivial as several challenges need to be overcome that are due to the electrically insulating and poor thermally conducting film and substrate."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Spin-torque-driven magnetization dynamics for neuromorphic functionality"]}]}],"canonical_facts":{"dc:contributor":["Hoffmann, Axel F.","Hoffmann, Axel F","Cahill, David G","Zuo, Jian-Min","Rakheja, Shaloo"],"dc:creator":["Klause, Robin"],"dc:date":["2025-05-19","2025-08"],"dc:description":["Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms","The student, Robin Klause, accepted the attached license on 2025-05-08 at 09:00.","The student, Robin Klause, submitted this Dissertation for approval on 2025-05-08 at 09:14.","This Dissertation was approved for publication on 2025-05-19 at 13:28.","DSpace SAF Submission Ingestion Package generated from Vireo submission #22128 on 2025-10-20 at 20:14:40","With the ever-increasing demand for computationally demanding tasks and large scale memory, new information processing and storage technology is needed. Spintronics plays a key role in the development of faster, smaller, and more energy efficient technology. In this work, the focus lies on the electrical control of magnetization dynamics through spin-orbit torques and the exploration of their potential for enabling neuromorphic functionality. More specifically, unconventional spin-orbit torques and the coupling of spin-Hall nano-oscillators are explored. First, unconventional spin-orbit torque generation in the non-collinear antiferromagnet and altermagnet Mn$_3$Pt is explored. The thin film growth process is optimized based on the structural characterization, and the electrical transport properties. Spin-torque ferromagnetic-resonance reveals that unconventional spin-orbit torques, resulting from a spin polarization component along the current direction, are generated when current is applied along specific directions with respect to the crystal and magnetic order. Second, unconventional spin-orbit torque generation in CrPt$_3$ is studied. Spin-torque ferromagnetic-resonance and second harmonic Hall measurements of CrPt$_3$/Cu/Ni$_{81}$Fe$_{19}$ heterostructures reveal that unconventional field-like spin-orbit torques are generated in both ferrimagnetic and paramagnetic CrPt$_3$ films indicating that the magnetic ordering does not play a role in generating unconventional torques. Instead, numerical calculations reveal that the unconventional torques stem from indirect non-local spin-orbit torques and symmetry breaking at the CrPt$_3$/Cu interface. Third, micromagnetic simulations show that unconventional spin-orbit torques can be used to generate magnetic droplet solitons in a ferromagnet with perpendicular magnetic anisotropy without applying an in-plane magnetic field. Due to the non-local injection of spin-orbit torques, which differs from the typical spin-valve geometry, multiple magnetic droplets can be generated and annihilated using specific current pulses. Last, Pt/Ni$_{81}$Fe$_{19}$ spin-Hall nano-oscillators are fabricated on Si substrate. Injection-locking of the oscillations to an {\\em rf} signal reveal that direct electrical coupling of two oscillators is unfeasible due to the low power generation of a spin-Hall nano-oscillator. However, the frequency behavior of two connected oscillators can be tuned using two voltage sources. In addition, a fabrication process for Pt/Ni$_{81}$Fe$_{19}$ oscillators on top of an Y$_3$Fe$_5$O$_{12}$ film that were grown on Gd$_3$Ga$_5$O$_{12}$ is developed. This is non-trivial as several challenges need to be overcome that are due to the electrically insulating and poor thermally conducting film and substrate."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/129895"],"dc:language":["en","eng"],"dc:rights":["Copyright 2025 Robin Klause"],"dc:subject":["Spintronics","Magnetic This Films","Spin-orbit Torques","Magnetization Dynamics"],"dc:title":["Spin-torque-driven magnetization dynamics for neuromorphic functionality"],"dc:type":["text"],"thesis:degree_discipline":["Materials Science & Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:06Z"}