{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/110409"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/110409","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Magnetic ordering and spin wave dynamics in transition metal arsenides","abstract":"Ever since spin orbit torque based switching was proposed in antiferromagnets, there is a growing interest in using a metallic antiferromagnet as an active component of a spintronic device. Arsenic forms a large pool of magnetic metals in combination with transition metal atoms. In this report, we explore compounds in Cu-Mn-As phase space by identifying the transition temperatures using calorimetry and magnetometry measurements, understanding the magnetic structure at different temperatures using neutron powder diffraction techniques, and using inelastic neutron scattering techniques to characterize exchange interactions in these materials. We discover a new ternary metallic arsenide Cu0.82Mn1.18As which crystallizes in the hexagonal crystal system and contains a frustrated in-plane triangular arrangement of Mn spins. We also identify the two-step transition in Mn3As2 from a paramagnet to a collinear ferrimagnet and then, into a canted spin state. Using high resolution synchrotron x-ray diffraction and neutron powder diffraction measurements, we identify magnetically coupled structural transitions in tetragonal CuMnAs which result from exchange frustration between the Mn moments and finite Cu moments. Finally, using single crystal inelastic neutron scattering measurements, we determine exchange interactions in Fe2As (same structure as CuMnAs) and show that it has a highly two dimensional magnon character although the phonon interactions are three dimensional in nature.","abstract_html":"Ever since spin orbit torque based switching was proposed in antiferromagnets, there is a growing interest in using a metallic antiferromagnet as an active component of a spintronic device. Arsenic forms a large pool of magnetic metals in combination with transition metal atoms. In this report, we explore compounds in Cu-Mn-As phase space by identifying the transition temperatures using calorimetry and magnetometry measurements, understanding the magnetic structure at different temperatures using neutron powder diffraction techniques, and using inelastic neutron scattering techniques to characterize exchange interactions in these materials. We discover a new ternary metallic arsenide Cu0.82Mn1.18As which crystallizes in the hexagonal crystal system and contains a frustrated in-plane triangular arrangement of Mn spins. We also identify the two-step transition in Mn3As2 from a paramagnet to a collinear ferrimagnet and then, into a canted spin state. Using high resolution synchrotron x-ray diffraction and neutron powder diffraction measurements, we identify magnetically coupled structural transitions in tetragonal CuMnAs which result from exchange frustration between the Mn moments and finite Cu moments. Finally, using single crystal inelastic neutron scattering measurements, we determine exchange interactions in Fe2As (same structure as CuMnAs) and show that it has a highly two dimensional magnon character although the phonon interactions are three dimensional in nature.","abstract_has_math":false,"creators":["Karigerasi, Manohar H."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science & Engr","degree_department":null,"school":null,"contributors":["Shoemaker, Daniel P","Cahill, David G","Zuo, Jian-Min","MacDougall, Gregory J"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2021,"date_issued":"2021-09-17T01:10:30Z","date_published":"2021-09-17T01:10:30Z","updated_at":"2026-07-22T22:24:50Z","subjects":["magnetic ordering","magnon spectra","metallic antiferromagnets","spintronics","exchange interactions","magnetic anisotropy","neutron diffraction","inelastic neutron scattering","x-ray diffraction","calorimetry","magnetometry","materials synthesis"],"languages":["en"],"rights":["Copyright 2021 Manohar H. Karigerasi"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/110409","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Shoemaker, Daniel P","Cahill, David G","Zuo, Jian-Min","MacDougall, Gregory J"]},{"key":"dc:creator","label":"Author","values":["Karigerasi, Manohar H."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2021-09-17T01:10:30Z","2021-01-28","2021-05"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"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 at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["magnetic ordering","magnon spectra","metallic antiferromagnets","spintronics","exchange interactions","magnetic anisotropy","neutron diffraction","inelastic neutron scattering","x-ray diffraction","calorimetry","magnetometry","materials synthesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2021 Manohar H. 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We discover a new ternary metallic arsenide Cu0.82Mn1.18As which crystallizes in the hexagonal crystal system and contains a frustrated in-plane triangular arrangement of Mn spins. We also identify the two-step transition in Mn3As2 from a paramagnet to a collinear ferrimagnet and then, into a canted spin state. Using high resolution synchrotron x-ray diffraction and neutron powder diffraction measurements, we identify magnetically coupled structural transitions in tetragonal CuMnAs which result from exchange frustration between the Mn moments and finite Cu moments. Finally, using single crystal inelastic neutron scattering measurements, we determine exchange interactions in Fe2As (same structure as CuMnAs) and show that it has a highly two dimensional magnon character although the phonon interactions are three dimensional in nature.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2021-09-16 without embargo terms","The student, Manohar Karigerasi, accepted the attached license on 2021-01-23 at 11:40.","The student, Manohar Karigerasi, submitted this Dissertation for approval on 2021-01-23 at 12:00.","This Dissertation was approved for publication on 2021-01-28 at 11:02.","DSpace SAF Submission Ingestion Package generated from Vireo submission #16154 on 2021-09-16 at 16:39:31","Made available in DSpace on 2021-09-17T01:10:30Z (GMT). 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Arsenic forms a large pool of magnetic metals in combination with transition metal atoms. In this report, we explore compounds in Cu-Mn-As phase space by identifying the transition temperatures using calorimetry and magnetometry measurements, understanding the magnetic structure at different temperatures using neutron powder diffraction techniques, and using inelastic neutron scattering techniques to characterize exchange interactions in these materials. We discover a new ternary metallic arsenide Cu0.82Mn1.18As which crystallizes in the hexagonal crystal system and contains a frustrated in-plane triangular arrangement of Mn spins. We also identify the two-step transition in Mn3As2 from a paramagnet to a collinear ferrimagnet and then, into a canted spin state. Using high resolution synchrotron x-ray diffraction and neutron powder diffraction measurements, we identify magnetically coupled structural transitions in tetragonal CuMnAs which result from exchange frustration between the Mn moments and finite Cu moments. Finally, using single crystal inelastic neutron scattering measurements, we determine exchange interactions in Fe2As (same structure as CuMnAs) and show that it has a highly two dimensional magnon character although the phonon interactions are three dimensional in nature.","Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2021-09-16 without embargo terms","The student, Manohar Karigerasi, accepted the attached license on 2021-01-23 at 11:40.","The student, Manohar Karigerasi, submitted this Dissertation for approval on 2021-01-23 at 12:00.","This Dissertation was approved for publication on 2021-01-28 at 11:02.","DSpace SAF Submission Ingestion Package generated from Vireo submission #16154 on 2021-09-16 at 16:39:31","Made available in DSpace on 2021-09-17T01:10:30Z (GMT). No. of bitstreams: 3 KARIGERASI-DISSERTATION-2021.pdf: 21155876 bytes, checksum: d2909efbc053636483407be96fa97885 (MD5) LICENSE.txt: 4215 bytes, checksum: 47eaf4c2b601dbbc871cb0fa634154a2 (MD5) PROQUEST_LICENSE.txt: 4561 bytes, checksum: f7c5bc3a42007f685982ec81cce9f6d2 (MD5) Previous issue date: 2021-01-28"],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/110409"],"dc:language":["en"],"dc:rights":["Copyright 2021 Manohar H. Karigerasi"],"dc:subject":["magnetic ordering","magnon spectra","metallic antiferromagnets","spintronics","exchange interactions","magnetic anisotropy","neutron diffraction","inelastic neutron scattering","x-ray diffraction","calorimetry","magnetometry","materials synthesis"],"dc:title":["Magnetic ordering and spin wave dynamics in transition metal arsenides"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Materials Science & Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:50Z"}