{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/106488"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/106488","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Magnon and phonon thermal transport in oxides","abstract":"Waste heat management and recovery and discovering energy-efficient devices are important problems that we need to solve. To solve these problems, one of the important thing that we need to understand is the thermal transport that happens inside the material. In my PhD work, I advanced the understanding of the mechanism of magnon and phonon thermal transport in oxides. In these studies, I use ultrafast pump-probe metrology, time-domain thermoreflectance to measure the thermal conductivity. The first subject is the relationship between magnons and phonons in low-dimensional quantum magnets, cuprates, which have high magnon thermal conductivity even at room temperature. At high temperatures, I observed that the cuprates still have large magnon contribution to its thermal conductivity even at temperatures larger than the bulk Neel temperature. In addition, the crystals with different spin structures have different temperature dependences. The second topic is on yttrium-iron-garnet, where I hope to understand the magnon-phonon thermal transport inside the YIG crystal, and also to understand the electron-magnon transport across metal-YIG interfaces. In particular, I would like to see how different deposition techniques can affect the thermal conductivity of YIG thin films. Knowing the thermal conductivity is important because YIG thin films are used for spin-Seebeck (SSE) applications, and thermal gradient is important in SSE application. I found that these thin films have lower thermal conductivities compared to the bulk YIG crystal and that GGG thermal conductivities are also lower than what were reported in the literature. In the third topic, I would like to understand the phonon transport inside (SrTiO3)nSrO (n=1-5 and 10) superlattice thin films. Superlattices have been an interest of many studies because of its potential application for energy-harvesting devices, such as thermoelectric devices. I would like to understand better if there is any coherent-incoherent phonon transport transition, like what was observed in graphene superlattice, or AlAs/GaAs superlattice or other oxide perovskites. In addition, I also measured the thermal conductivity of films with various interface density, but no observable incoherent-coherent phonon transition was observed. Finally, I was able to map the thermal conductivity of SiC ceramic matrix composite (CMC) using TDTR. SiC composite has been a subject of study interest because of its potential application for nuclear fuel cladding. However, existing models only used the effective thermal conductivity or only assumed that the thermal property of each material, such as matrix, fiber, and interphase, to stay the same before and after their incorporation into the composite. In this study, I reported the thermal conductivity of each constituent and their temperature dependences. The matrix has varying thermal conductivity from 50 to 120 W/m-K, and it is approximately dependent on 1/T1/2. The fiber has a uniform thermal conductivity of 22 W/m-K, and it is relatively independent of temperature.","abstract_html":"Waste heat management and recovery and discovering energy-efficient devices are important problems that we need to solve. To solve these problems, one of the important thing that we need to understand is the thermal transport that happens inside the material. In my PhD work, I advanced the understanding of the mechanism of magnon and phonon thermal transport in oxides. In these studies, I use ultrafast pump-probe metrology, time-domain thermoreflectance to measure the thermal conductivity. The first subject is the relationship between magnons and phonons in low-dimensional quantum magnets, cuprates, which have high magnon thermal conductivity even at room temperature. At high temperatures, I observed that the cuprates still have large magnon contribution to its thermal conductivity even at temperatures larger than the bulk Neel temperature. In addition, the crystals with different spin structures have different temperature dependences. The second topic is on yttrium-iron-garnet, where I hope to understand the magnon-phonon thermal transport inside the YIG crystal, and also to understand the electron-magnon transport across metal-YIG interfaces. In particular, I would like to see how different deposition techniques can affect the thermal conductivity of YIG thin films. Knowing the thermal conductivity is important because YIG thin films are used for spin-Seebeck (SSE) applications, and thermal gradient is important in SSE application. I found that these thin films have lower thermal conductivities compared to the bulk YIG crystal and that GGG thermal conductivities are also lower than what were reported in the literature. In the third topic, I would like to understand the phonon transport inside (SrTiO3)nSrO (n=1-5 and 10) superlattice thin films. Superlattices have been an interest of many studies because of its potential application for energy-harvesting devices, such as thermoelectric devices. I would like to understand better if there is any coherent-incoherent phonon transport transition, like what was observed in graphene superlattice, or AlAs/GaAs superlattice or other oxide perovskites. In addition, I also measured the thermal conductivity of films with various interface density, but no observable incoherent-coherent phonon transition was observed. Finally, I was able to map the thermal conductivity of SiC ceramic matrix composite (CMC) using TDTR. SiC composite has been a subject of study interest because of its potential application for nuclear fuel cladding. However, existing models only used the effective thermal conductivity or only assumed that the thermal property of each material, such as matrix, fiber, and interphase, to stay the same before and after their incorporation into the composite. In this study, I reported the thermal conductivity of each constituent and their temperature dependences. The matrix has varying thermal conductivity from 50 to 120 W/m-K, and it is approximately dependent on 1/T1/2. The fiber has a uniform thermal conductivity of 22 W/m-K, and it is relatively independent of temperature.","abstract_has_math":false,"creators":["Pek, Ella Kartika Putihprayogi"],"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":["Cahill, David G","Cooper, S. Lance","Schleife, Andre","Krogstad, Jessica"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-03-02T22:38:57Z","date_published":"2020-03-02T22:38:57Z","updated_at":"2026-07-22T22:24:47Z","subjects":["Thermal Mapping","Cuprates","Thermal Transport","Phonon","Magnon","YIG","SiC composite","Epitaxial Thin Film"],"languages":["en"],"rights":["Copyright 2019 Ella Kartika Putihprayogi Pek"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/106488","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Cahill, David G","Cooper, S. 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To solve these problems, one of the important thing that we need to understand is the thermal transport that happens inside the material. In my PhD work, I advanced the understanding of the mechanism of magnon and phonon thermal transport in oxides. In these studies, I use ultrafast pump-probe metrology, time-domain thermoreflectance to measure the thermal conductivity. The first subject is the relationship between magnons and phonons in low-dimensional quantum magnets, cuprates, which have high magnon thermal conductivity even at room temperature. At high temperatures, I observed that the cuprates still have large magnon contribution to its thermal conductivity even at temperatures larger than the bulk Neel temperature. In addition, the crystals with different spin structures have different temperature dependences. The second topic is on yttrium-iron-garnet, where I hope to understand the magnon-phonon thermal transport inside the YIG crystal, and also to understand the electron-magnon transport across metal-YIG interfaces. In particular, I would like to see how different deposition techniques can affect the thermal conductivity of YIG thin films. Knowing the thermal conductivity is important because YIG thin films are used for spin-Seebeck (SSE) applications, and thermal gradient is important in SSE application. I found that these thin films have lower thermal conductivities compared to the bulk YIG crystal and that GGG thermal conductivities are also lower than what were reported in the literature. In the third topic, I would like to understand the phonon transport inside (SrTiO3)nSrO (n=1-5 and 10) superlattice thin films. Superlattices have been an interest of many studies because of its potential application for energy-harvesting devices, such as thermoelectric devices. I would like to understand better if there is any coherent-incoherent phonon transport transition, like what was observed in graphene superlattice, or AlAs/GaAs superlattice or other oxide perovskites. In addition, I also measured the thermal conductivity of films with various interface density, but no observable incoherent-coherent phonon transition was observed. Finally, I was able to map the thermal conductivity of SiC ceramic matrix composite (CMC) using TDTR. SiC composite has been a subject of study interest because of its potential application for nuclear fuel cladding. However, existing models only used the effective thermal conductivity or only assumed that the thermal property of each material, such as matrix, fiber, and interphase, to stay the same before and after their incorporation into the composite. In this study, I reported the thermal conductivity of each constituent and their temperature dependences. The matrix has varying thermal conductivity from 50 to 120 W/m-K, and it is approximately dependent on 1/T1/2. The fiber has a uniform thermal conductivity of 22 W/m-K, and it is relatively independent of temperature.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-12-01","The student, Ella Pek, accepted the attached license on 2019-12-04 at 16:23.","The student, Ella Pek, submitted this Dissertation for approval on 2019-12-04 at 16:24.","This Dissertation was approved for publication on 2019-12-06 at 13:55.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14699 on 2020-02-28 at 17:37:57","Made available in DSpace on 2020-03-02T22:38:57Z (GMT). No. of bitstreams: 2 PEK-DISSERTATION-2019.pdf: 4100417 bytes, checksum: 18eb048f82836d56fc37d3af856024a0 (MD5) LICENSE.txt: 4205 bytes, checksum: 299102d118c5528cedbdb8bca6615a99 (MD5) Previous issue date: 2019-12-06","Embargo set by: Seth Robbins for item 114032 Lift date: 2022-03-02T22:39:04Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 114032 on 2022-03-03T10:15:13Z."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Magnon and phonon thermal transport in oxides"]}]}],"canonical_facts":{"dc:contributor":["Cahill, David G","Cooper, S. Lance","Schleife, Andre","Krogstad, Jessica"],"dc:creator":["Pek, Ella Kartika Putihprayogi"],"dc:date":["2020-03-02T22:38:57Z","2022-03-03T10:15:13Z","2019-12-06","2019-12"],"dc:description":["Waste heat management and recovery and discovering energy-efficient devices are important problems that we need to solve. To solve these problems, one of the important thing that we need to understand is the thermal transport that happens inside the material. In my PhD work, I advanced the understanding of the mechanism of magnon and phonon thermal transport in oxides. In these studies, I use ultrafast pump-probe metrology, time-domain thermoreflectance to measure the thermal conductivity. The first subject is the relationship between magnons and phonons in low-dimensional quantum magnets, cuprates, which have high magnon thermal conductivity even at room temperature. At high temperatures, I observed that the cuprates still have large magnon contribution to its thermal conductivity even at temperatures larger than the bulk Neel temperature. In addition, the crystals with different spin structures have different temperature dependences. The second topic is on yttrium-iron-garnet, where I hope to understand the magnon-phonon thermal transport inside the YIG crystal, and also to understand the electron-magnon transport across metal-YIG interfaces. In particular, I would like to see how different deposition techniques can affect the thermal conductivity of YIG thin films. Knowing the thermal conductivity is important because YIG thin films are used for spin-Seebeck (SSE) applications, and thermal gradient is important in SSE application. I found that these thin films have lower thermal conductivities compared to the bulk YIG crystal and that GGG thermal conductivities are also lower than what were reported in the literature. In the third topic, I would like to understand the phonon transport inside (SrTiO3)nSrO (n=1-5 and 10) superlattice thin films. Superlattices have been an interest of many studies because of its potential application for energy-harvesting devices, such as thermoelectric devices. I would like to understand better if there is any coherent-incoherent phonon transport transition, like what was observed in graphene superlattice, or AlAs/GaAs superlattice or other oxide perovskites. In addition, I also measured the thermal conductivity of films with various interface density, but no observable incoherent-coherent phonon transition was observed. Finally, I was able to map the thermal conductivity of SiC ceramic matrix composite (CMC) using TDTR. SiC composite has been a subject of study interest because of its potential application for nuclear fuel cladding. However, existing models only used the effective thermal conductivity or only assumed that the thermal property of each material, such as matrix, fiber, and interphase, to stay the same before and after their incorporation into the composite. In this study, I reported the thermal conductivity of each constituent and their temperature dependences. The matrix has varying thermal conductivity from 50 to 120 W/m-K, and it is approximately dependent on 1/T1/2. The fiber has a uniform thermal conductivity of 22 W/m-K, and it is relatively independent of temperature.","Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-12-01","The student, Ella Pek, accepted the attached license on 2019-12-04 at 16:23.","The student, Ella Pek, submitted this Dissertation for approval on 2019-12-04 at 16:24.","This Dissertation was approved for publication on 2019-12-06 at 13:55.","DSpace SAF Submission Ingestion Package generated from Vireo submission #14699 on 2020-02-28 at 17:37:57","Made available in DSpace on 2020-03-02T22:38:57Z (GMT). No. of bitstreams: 2 PEK-DISSERTATION-2019.pdf: 4100417 bytes, checksum: 18eb048f82836d56fc37d3af856024a0 (MD5) LICENSE.txt: 4205 bytes, checksum: 299102d118c5528cedbdb8bca6615a99 (MD5) Previous issue date: 2019-12-06","Embargo set by: Seth Robbins for item 114032 Lift date: 2022-03-02T22:39:04Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system","Limited Restriction Lifted for Item 114032 on 2022-03-03T10:15:13Z."],"dc:format":["application/pdf"],"dc:identifier":["http://hdl.handle.net/2142/106488"],"dc:language":["en"],"dc:rights":["Copyright 2019 Ella Kartika Putihprayogi Pek"],"dc:subject":["Thermal Mapping","Cuprates","Thermal Transport","Phonon","Magnon","YIG","SiC composite","Epitaxial Thin Film"],"dc:title":["Magnon and phonon thermal transport in oxides"],"dc:type":["text"],"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":"2026-07-22T22:24:47Z"}