Magnetismo de baixa dimensão no Fe1-xCuxNbO4
Ano de defesa: | 2023 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | |
Tipo de documento: | Tese |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Não Informado pela instituição
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Programa de Pós-Graduação: |
Pós-Graduação em Física
|
Departamento: |
Não Informado pela instituição
|
País: |
Não Informado pela instituição
|
Palavras-chave em Português: | |
Palavras-chave em Inglês: | |
Área do conhecimento CNPq: | |
Link de acesso: | https://ri.ufs.br/jspui/handle/riufs/18248 |
Resumo: | In the present work, iron and copper niobates (Fe1xCuxNbO4 with x = 0 - 0.15 and 0.25) were prepared by the modified solid state method and characterized by diffraction of X-rays (XRD), scanning electron microscopy (SEM/EDX), Mössbauer spectroscopy (EM), temperature-dependent (10 - 1000 K) and magnetic field Raman spectroscopy (ER), magnetic measurements as a function of temperature (M-T, 1.8 - 1000 K) and magnetic field (M-H) and measurements of AC magnetic susceptibility as a function of frequency and DC field. The results (DRXs and ER) confirm the phase (mFeNbO4), as well as the local influences caused by the insertion of Cu ions. SEM suggests a non-uniform particle size distribution with a mean diameter of 1.62 µm. Magnetic analyzes (M - H and M - T) confirmed that the FeNbO4 structure presents an antiferromagnetic (AFM) ordering state, with temperature TN ~36.81 K and revealed an antiferromagnetic-ferrimagnetic transition (AFM-FIM) due to the replacement of Fe3+ ions by Cu2+ ions in Fe1-xCuxNbO4 (x > 0.05), which remains above ambient temperature. The analysis by study of the magnetocaloric effect (EMC), through the analysis of the temperature-dependent variation of magnetic entropy (SM) in different magnetic fields (1 to 7 T), confirms the transition of the magnetic order from AFM to FIM, with a transition temperature of T´N = 38 K, for sample Fe0.75Cu0.25NbO4. AC magnetic susceptibility measurements (Xac(T,f ) and Xac(T,f ,H)), show that, at low temperatures, the insertion of Cu2+ causes an increase in magnetic anisotropy and, in the absence of long range order (LRO) it promotes slow magnetic relaxation processes, between 52 and 163 K, which strongly resemble the behavior of a single-chain magnet (SCM). The magnetic studies at high temperatures showed the magnetic transition FIM-PM (ferrimagnetic-paramagnetic) with TC = 908 K, through measurements of temperature-dependent magnetization (M-T) and evidenced by Raman spectroscopy dependent on temperature and field. We also report the direct observation of the magnetic excitation of two magnons and the couplings of magnons-phonons, spin-phonons in the FIM-PM magnetic transition region for Fe0.75Cu0.25NbO4, via temperature-dependent Raman spectroscopy. |
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Evaristo, Diego da SilvaMacêdo, Marcelo Andrade2023-09-04T16:42:31Z2023-09-04T16:42:31Z2023-07-28EVARISTO, Diego da Silva. Magnetismo de baixa dimensão no Fe1-xCuxNbO4. 2023. 133 f. Tese (Doutorado em Física) – Universidade Federal de Sergipe, São Cristóvão, 2023.https://ri.ufs.br/jspui/handle/riufs/18248In the present work, iron and copper niobates (Fe1xCuxNbO4 with x = 0 - 0.15 and 0.25) were prepared by the modified solid state method and characterized by diffraction of X-rays (XRD), scanning electron microscopy (SEM/EDX), Mössbauer spectroscopy (EM), temperature-dependent (10 - 1000 K) and magnetic field Raman spectroscopy (ER), magnetic measurements as a function of temperature (M-T, 1.8 - 1000 K) and magnetic field (M-H) and measurements of AC magnetic susceptibility as a function of frequency and DC field. The results (DRXs and ER) confirm the phase (mFeNbO4), as well as the local influences caused by the insertion of Cu ions. SEM suggests a non-uniform particle size distribution with a mean diameter of 1.62 µm. Magnetic analyzes (M - H and M - T) confirmed that the FeNbO4 structure presents an antiferromagnetic (AFM) ordering state, with temperature TN ~36.81 K and revealed an antiferromagnetic-ferrimagnetic transition (AFM-FIM) due to the replacement of Fe3+ ions by Cu2+ ions in Fe1-xCuxNbO4 (x > 0.05), which remains above ambient temperature. The analysis by study of the magnetocaloric effect (EMC), through the analysis of the temperature-dependent variation of magnetic entropy (SM) in different magnetic fields (1 to 7 T), confirms the transition of the magnetic order from AFM to FIM, with a transition temperature of T´N = 38 K, for sample Fe0.75Cu0.25NbO4. AC magnetic susceptibility measurements (Xac(T,f ) and Xac(T,f ,H)), show that, at low temperatures, the insertion of Cu2+ causes an increase in magnetic anisotropy and, in the absence of long range order (LRO) it promotes slow magnetic relaxation processes, between 52 and 163 K, which strongly resemble the behavior of a single-chain magnet (SCM). The magnetic studies at high temperatures showed the magnetic transition FIM-PM (ferrimagnetic-paramagnetic) with TC = 908 K, through measurements of temperature-dependent magnetization (M-T) and evidenced by Raman spectroscopy dependent on temperature and field. We also report the direct observation of the magnetic excitation of two magnons and the couplings of magnons-phonons, spin-phonons in the FIM-PM magnetic transition region for Fe0.75Cu0.25NbO4, via temperature-dependent Raman spectroscopy.No presente trabalho, niobatos de ferro e cobre (Fe1-xCuxNbO4 com x = 0 - 0.15 e 0.25), foram preparados pelo método do estado sólido modificado e caracterizados por difração de raios X (DRX), microscopia eletrônica de varredura (MEV/EDX), espectroscopia Mössbauer (EM), espectroscopia Raman (ER) dependente da temperatura (10 - 1000 K) e campo magnético, medidas magnéticas em função da temperatura (M-T, 1.8 - 1000 K) e campo magnético (M-H) e medidas de suscetibilidade magnética AC em função da frequência e campo DC. Os resultados (DRXs e ER) confirmam a fase (m-FeNbO4), bem como, as influências locais provocadas pela inserção de íons de Cu. O MEV sugere uma distribuição não uniforme de tamanho de partículas com diâmetro médio de 1.62 µm. Análises magnéticas (M - H e M - T ) confirmaram que a estrutura FeNbO4 apresenta um estado de ordenação antiferromagnético (AFM), com temperatura TN ~36,81 K e revelaram uma transição antiferromagnética- ferrimagnética (AFM-FIM) em função da substituição de íons de Fe3+ por íons Cu2+ na Fe1-xCuxNbO4 (x > 0.05), que permanece acima da temperatura ambiente. A análise por estudo do efeito magnetocalórico (EMC), através da análise da variação da entropia magnética dependente da temperatura (delta SM) em diferentes campos magnéticos (1 a 7 T), confirma a transição da ordem magnética de AFM para FIM, com uma temperatura de transição de T´N = 38 K, para amostra Fe0.75Cu0.25NbO4. Medidas de suscetibilidade magnética AC (Xac(T,f ) e Xac(T,f ,H)), mostram que, em baixas temperaturas, a inserção de Cu2+ provoca um aumento na anisotropia magnética e, na ausência de ordem de longo alcance (LRO) promove processos de relaxações magnéticas lentos, entre 52 e 163 K, que se assemelham fortemente ao comportamento de um magneto da cadeia única (SCM). Os estudos magnéticos em altas temperaturas mostraram a transição magnética FIM-PM (ferrimagnética-paramagnética) com T C = 908 K, através de medidas de magnetização dependente da temperatura (M - T) e evidenciada por espectroscopia Raman dependente da temperatura e campo. Relatamos também a observação direta da excitação magnética de dois mágnons e dos acoplamentos mágnons-fônons, spin-fônons na região de transição magnética FIM-PM para Fe0.75Cu0.25NbO4, via espectroscopia Raman dependente da temperatura.Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPqSão CristóvãoporTransição de fase magnéticaDinâmica de spin lentoEfeito HopkinsonAcoplamento spin-fônonMágnonAcoplamento mágnon-fônonMagnetic phase transitionSlow spin dynamicsHopkinson effectSpin-phonon couplingMagnonMagnon-phonon couplingCIENCIAS EXATAS E DA TERRA::FISICAMagnetismo de baixa dimensão no Fe1-xCuxNbO4info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisPós-Graduação em FísicaUniversidade Federal de Sergipe (UFS)reponame:Repositório Institucional da UFSinstname:Universidade Federal de Sergipe (UFS)instacron:UFSinfo:eu-repo/semantics/openAccessLICENSElicense.txtlicense.txttext/plain; charset=utf-81475https://ri.ufs.br/jspui/bitstream/riufs/18248/1/license.txt098cbbf65c2c15e1fb2e49c5d306a44cMD51ORIGINALDIEGO_SILVA_EVARISTO.pdfDIEGO_SILVA_EVARISTO.pdfapplication/pdf39438889https://ri.ufs.br/jspui/bitstream/riufs/18248/2/DIEGO_SILVA_EVARISTO.pdfc7ca9340a67eb303956a808241dc1a87MD52TEXTDIEGO_SILVA_EVARISTO.pdf.txtDIEGO_SILVA_EVARISTO.pdf.txtExtracted texttext/plain234057https://ri.ufs.br/jspui/bitstream/riufs/18248/3/DIEGO_SILVA_EVARISTO.pdf.txteb806589731dd36bb4fed53eca15d217MD53THUMBNAILDIEGO_SILVA_EVARISTO.pdf.jpgDIEGO_SILVA_EVARISTO.pdf.jpgGenerated Thumbnailimage/jpeg1346https://ri.ufs.br/jspui/bitstream/riufs/18248/4/DIEGO_SILVA_EVARISTO.pdf.jpg77c932153a353a491869d5413afc829bMD54riufs/182482023-09-04 13:42:50.168oai:ufs.br:riufs/18248TElDRU7Dh0EgREUgRElTVFJJQlVJw4fDg08gTsODTy1FWENMVVNJVkEKCkNvbSBhIGFwcmVzZW50YcOnw6NvIGRlc3RhIGxpY2Vuw6dhLCB2b2PDqiAobyBhdXRvcihlcykgb3UgbyB0aXR1bGFyIGRvcyBkaXJlaXRvcyBkZSBhdXRvcikgY29uY2VkZSDDoCBVbml2ZXJzaWRhZGUgRmVkZXJhbCBkZSBTZXJnaXBlIG8gZGlyZWl0byBuw6NvLWV4Y2x1c2l2byBkZSByZXByb2R1emlyIHNldSB0cmFiYWxobyBubyBmb3JtYXRvIGVsZXRyw7RuaWNvLCBpbmNsdWluZG8gb3MgZm9ybWF0b3Mgw6F1ZGlvIG91IHbDrWRlby4KClZvY8OqIGNvbmNvcmRhIHF1ZSBhIFVuaXZlcnNpZGFkZSBGZWRlcmFsIGRlIFNlcmdpcGUgcG9kZSwgc2VtIGFsdGVyYXIgbyBjb250ZcO6ZG8sIHRyYW5zcG9yIHNldSB0cmFiYWxobyBwYXJhIHF1YWxxdWVyIG1laW8gb3UgZm9ybWF0byBwYXJhIGZpbnMgZGUgcHJlc2VydmHDp8Ojby4KClZvY8OqIHRhbWLDqW0gY29uY29yZGEgcXVlIGEgVW5pdmVyc2lkYWRlIEZlZGVyYWwgZGUgU2VyZ2lwZSBwb2RlIG1hbnRlciBtYWlzIGRlIHVtYSBjw7NwaWEgZGUgc2V1IHRyYWJhbGhvIHBhcmEgZmlucyBkZSBzZWd1cmFuw6dhLCBiYWNrLXVwIGUgcHJlc2VydmHDp8Ojby4KClZvY8OqIGRlY2xhcmEgcXVlIHNldSB0cmFiYWxobyDDqSBvcmlnaW5hbCBlIHF1ZSB2b2PDqiB0ZW0gbyBwb2RlciBkZSBjb25jZWRlciBvcyBkaXJlaXRvcyBjb250aWRvcyBuZXN0YSBsaWNlbsOnYS4gVm9jw6ogdGFtYsOpbSBkZWNsYXJhIHF1ZSBvIGRlcMOzc2l0bywgcXVlIHNlamEgZGUgc2V1IGNvbmhlY2ltZW50bywgbsOjbyBpbmZyaW5nZSBkaXJlaXRvcyBhdXRvcmFpcyBkZSBuaW5ndcOpbS4KCkNhc28gbyB0cmFiYWxobyBjb250ZW5oYSBtYXRlcmlhbCBxdWUgdm9jw6ogbsOjbyBwb3NzdWkgYSB0aXR1bGFyaWRhZGUgZG9zIGRpcmVpdG9zIGF1dG9yYWlzLCB2b2PDqiBkZWNsYXJhIHF1ZSBvYnRldmUgYSBwZXJtaXNzw6NvIGlycmVzdHJpdGEgZG8gZGV0ZW50b3IgZG9zIGRpcmVpdG9zIGF1dG9yYWlzIHBhcmEgY29uY2VkZXIgw6AgVW5pdmVyc2lkYWRlIEZlZGVyYWwgZGUgU2VyZ2lwZSBvcyBkaXJlaXRvcyBhcHJlc2VudGFkb3MgbmVzdGEgbGljZW7Dp2EsIGUgcXVlIGVzc2UgbWF0ZXJpYWwgZGUgcHJvcHJpZWRhZGUgZGUgdGVyY2Vpcm9zIGVzdMOhIGNsYXJhbWVudGUgaWRlbnRpZmljYWRvIGUgcmVjb25oZWNpZG8gbm8gdGV4dG8gb3Ugbm8gY29udGXDumRvLgoKQSBVbml2ZXJzaWRhZGUgRmVkZXJhbCBkZSBTZXJnaXBlIHNlIGNvbXByb21ldGUgYSBpZGVudGlmaWNhciBjbGFyYW1lbnRlIG8gc2V1IG5vbWUocykgb3UgbyhzKSBub21lKHMpIGRvKHMpIApkZXRlbnRvcihlcykgZG9zIGRpcmVpdG9zIGF1dG9yYWlzIGRvIHRyYWJhbGhvLCBlIG7Do28gZmFyw6EgcXVhbHF1ZXIgYWx0ZXJhw6fDo28sIGFsw6ltIGRhcXVlbGFzIGNvbmNlZGlkYXMgcG9yIGVzdGEgbGljZW7Dp2EuIAo=Repositório InstitucionalPUBhttps://ri.ufs.br/oai/requestrepositorio@academico.ufs.bropendoar:2023-09-04T16:42:50Repositório Institucional da UFS - Universidade Federal de Sergipe (UFS)false |
dc.title.pt_BR.fl_str_mv |
Magnetismo de baixa dimensão no Fe1-xCuxNbO4 |
title |
Magnetismo de baixa dimensão no Fe1-xCuxNbO4 |
spellingShingle |
Magnetismo de baixa dimensão no Fe1-xCuxNbO4 Evaristo, Diego da Silva Transição de fase magnética Dinâmica de spin lento Efeito Hopkinson Acoplamento spin-fônon Mágnon Acoplamento mágnon-fônon Magnetic phase transition Slow spin dynamics Hopkinson effect Spin-phonon coupling Magnon Magnon-phonon coupling CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Magnetismo de baixa dimensão no Fe1-xCuxNbO4 |
title_full |
Magnetismo de baixa dimensão no Fe1-xCuxNbO4 |
title_fullStr |
Magnetismo de baixa dimensão no Fe1-xCuxNbO4 |
title_full_unstemmed |
Magnetismo de baixa dimensão no Fe1-xCuxNbO4 |
title_sort |
Magnetismo de baixa dimensão no Fe1-xCuxNbO4 |
author |
Evaristo, Diego da Silva |
author_facet |
Evaristo, Diego da Silva |
author_role |
author |
dc.contributor.author.fl_str_mv |
Evaristo, Diego da Silva |
dc.contributor.advisor1.fl_str_mv |
Macêdo, Marcelo Andrade |
contributor_str_mv |
Macêdo, Marcelo Andrade |
dc.subject.por.fl_str_mv |
Transição de fase magnética Dinâmica de spin lento Efeito Hopkinson Acoplamento spin-fônon Mágnon Acoplamento mágnon-fônon |
topic |
Transição de fase magnética Dinâmica de spin lento Efeito Hopkinson Acoplamento spin-fônon Mágnon Acoplamento mágnon-fônon Magnetic phase transition Slow spin dynamics Hopkinson effect Spin-phonon coupling Magnon Magnon-phonon coupling CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.eng.fl_str_mv |
Magnetic phase transition Slow spin dynamics Hopkinson effect Spin-phonon coupling Magnon Magnon-phonon coupling |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::FISICA |
description |
In the present work, iron and copper niobates (Fe1xCuxNbO4 with x = 0 - 0.15 and 0.25) were prepared by the modified solid state method and characterized by diffraction of X-rays (XRD), scanning electron microscopy (SEM/EDX), Mössbauer spectroscopy (EM), temperature-dependent (10 - 1000 K) and magnetic field Raman spectroscopy (ER), magnetic measurements as a function of temperature (M-T, 1.8 - 1000 K) and magnetic field (M-H) and measurements of AC magnetic susceptibility as a function of frequency and DC field. The results (DRXs and ER) confirm the phase (mFeNbO4), as well as the local influences caused by the insertion of Cu ions. SEM suggests a non-uniform particle size distribution with a mean diameter of 1.62 µm. Magnetic analyzes (M - H and M - T) confirmed that the FeNbO4 structure presents an antiferromagnetic (AFM) ordering state, with temperature TN ~36.81 K and revealed an antiferromagnetic-ferrimagnetic transition (AFM-FIM) due to the replacement of Fe3+ ions by Cu2+ ions in Fe1-xCuxNbO4 (x > 0.05), which remains above ambient temperature. The analysis by study of the magnetocaloric effect (EMC), through the analysis of the temperature-dependent variation of magnetic entropy (SM) in different magnetic fields (1 to 7 T), confirms the transition of the magnetic order from AFM to FIM, with a transition temperature of T´N = 38 K, for sample Fe0.75Cu0.25NbO4. AC magnetic susceptibility measurements (Xac(T,f ) and Xac(T,f ,H)), show that, at low temperatures, the insertion of Cu2+ causes an increase in magnetic anisotropy and, in the absence of long range order (LRO) it promotes slow magnetic relaxation processes, between 52 and 163 K, which strongly resemble the behavior of a single-chain magnet (SCM). The magnetic studies at high temperatures showed the magnetic transition FIM-PM (ferrimagnetic-paramagnetic) with TC = 908 K, through measurements of temperature-dependent magnetization (M-T) and evidenced by Raman spectroscopy dependent on temperature and field. We also report the direct observation of the magnetic excitation of two magnons and the couplings of magnons-phonons, spin-phonons in the FIM-PM magnetic transition region for Fe0.75Cu0.25NbO4, via temperature-dependent Raman spectroscopy. |
publishDate |
2023 |
dc.date.accessioned.fl_str_mv |
2023-09-04T16:42:31Z |
dc.date.available.fl_str_mv |
2023-09-04T16:42:31Z |
dc.date.issued.fl_str_mv |
2023-07-28 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
EVARISTO, Diego da Silva. Magnetismo de baixa dimensão no Fe1-xCuxNbO4. 2023. 133 f. Tese (Doutorado em Física) – Universidade Federal de Sergipe, São Cristóvão, 2023. |
dc.identifier.uri.fl_str_mv |
https://ri.ufs.br/jspui/handle/riufs/18248 |
identifier_str_mv |
EVARISTO, Diego da Silva. Magnetismo de baixa dimensão no Fe1-xCuxNbO4. 2023. 133 f. Tese (Doutorado em Física) – Universidade Federal de Sergipe, São Cristóvão, 2023. |
url |
https://ri.ufs.br/jspui/handle/riufs/18248 |
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por |
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Pós-Graduação em Física |
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Universidade Federal de Sergipe (UFS) |
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