Estudo de modelos de spins com interação Dzyaloshinskii-Moriya
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFS |
Texto Completo: | https://ri.ufs.br/jspui/handle/riufs/18655 |
Resumo: | The critical properties of systems that exhibit magnetism have been the subject of intense research over the years. The study of the critical behavior of many magnetic, insulating and anisotropic materials can be approached through Ising and Heisenberg models, for exemple. Taking into account anisotropic effects in spin models usually results in the presence of tricritical behavior in the phase diagram. In particular, the Dzyaloshinskii-Moriya interaction consists of an important type of anisotropy, which has attracted attention over the last decades, playing an important role in the description of some classes of insulators, as well as in the study of phenomena involving chirality, among others. The presence of disorder in the models, introduced through random variables governed by probability distributions, also results in a change in critical behavior in relation to pure systems. In this thesis, the ferromagnetic anisotropic Heisenberg model with Dzyaloshinskii-Moriya interaction is studied in spin-3/2 and spin-2 versions within the pair approximation. The formalism can be applied to different types of lattice. However, the results presented here deal in detail with the case of the simple cubic lattice (q = 6). The phase diagrams and magnetic properties reveal the existence of tricritical points and first-order phase transitions. For the spin-1 model, cases involving the disorder generated from the inclusion of a random field are treated. In addition, some results with the application of the effective field theory, as well as the antiferromagnetic model, are discussed. |
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Silva, Joeliton Barros daAlbuquerque, Douglas Ferreira de2023-11-14T20:59:03Z2023-11-14T20:59:03Z2022-09-21SILVA, Joeliton Barros da. Estudo de modelos de spins com interação Dzyaloshinskii-Moriya. 2022. 103 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2022.https://ri.ufs.br/jspui/handle/riufs/18655The critical properties of systems that exhibit magnetism have been the subject of intense research over the years. The study of the critical behavior of many magnetic, insulating and anisotropic materials can be approached through Ising and Heisenberg models, for exemple. Taking into account anisotropic effects in spin models usually results in the presence of tricritical behavior in the phase diagram. In particular, the Dzyaloshinskii-Moriya interaction consists of an important type of anisotropy, which has attracted attention over the last decades, playing an important role in the description of some classes of insulators, as well as in the study of phenomena involving chirality, among others. The presence of disorder in the models, introduced through random variables governed by probability distributions, also results in a change in critical behavior in relation to pure systems. In this thesis, the ferromagnetic anisotropic Heisenberg model with Dzyaloshinskii-Moriya interaction is studied in spin-3/2 and spin-2 versions within the pair approximation. The formalism can be applied to different types of lattice. However, the results presented here deal in detail with the case of the simple cubic lattice (q = 6). The phase diagrams and magnetic properties reveal the existence of tricritical points and first-order phase transitions. For the spin-1 model, cases involving the disorder generated from the inclusion of a random field are treated. In addition, some results with the application of the effective field theory, as well as the antiferromagnetic model, are discussed.As propriedades críticas de sistemas que exibem magnetismo têm sido objeto de intensa pesquisa ao longo dos anos. O estudo do comportamento crítico de muitos materiais magnéticos, isolantes e anisotrópicos pode ser abordado através de modelos tais como Ising e Heisenberg. A consideração de efeitos anisotrópicos em modelos de spins usualmente resulta na presença de comportamento tricrítico no diagrama de fases. Em particular, a interação Dzyaloshinskii-Moriya consiste em um importante tipo de anisotropia, que tem atraído atenção ao longo das últimas décadas, desempenhando um papel relevante na descrição de algumas classes de isolantes, bem como no estudo dos fenômenos envolvendo quiralidade, dentre outros. A presença de desordem nos modelos, introduzida através de variáveis aleatórias governadas por distribuições de probabilidades, também resulta na alteração do comportamento crítico em relação a sistemas puros. Nesta tese, o modelo de Heisenberg anisotrópico ferromagnético com interação Dzyaloshinskii-Moriya é estudado nas versões spin-3/2 e spin-2 através de uma aproximação de pares. O formalismo pode ser aplicado a diversos tipos de redes. Contudo, os resultados aqui apresentados tratam em detalhes o caso da rede cúbica simples (q = 6). Os diagramas de fases e as propriedades magnéticas investigados revelam a existência de pontos tricríticos e transições de fase de primeira ordem. Para o modelo de spin-1, são tratados os casos envolvendo a desordem gerada a partir da inclusão de campo aleatório. Além disso, alguns resultados com aplicação da teoria de campo efetivo, bem como o modelo antiferromagnético são discutidos.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESFundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SESão CristóvãoporInteração Dzyaloshinskii-MoriyaTransições de fasesModelo de HeisenbergCampo aleatórioPonto tricríticoDzyaloshinskii-Moriya interactionPhase transitionsHeisenberg modelRandom fieldTricritical pointCIENCIAS EXATAS E DA TERRA::FISICAEstudo de modelos de spins com interação Dzyaloshinskii-Moriyainfo: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/18655/1/license.txt098cbbf65c2c15e1fb2e49c5d306a44cMD51ORIGINALJOELITON_BARROS_SILVA.pdfJOELITON_BARROS_SILVA.pdfapplication/pdf4295750https://ri.ufs.br/jspui/bitstream/riufs/18655/2/JOELITON_BARROS_SILVA.pdfc5b4de87c768fc1006714f14d2f258e4MD52TEXTJOELITON_BARROS_SILVA.pdf.txtJOELITON_BARROS_SILVA.pdf.txtExtracted texttext/plain183513https://ri.ufs.br/jspui/bitstream/riufs/18655/3/JOELITON_BARROS_SILVA.pdf.txt77bab12cb0b27db197e8fee4f98caef0MD53THUMBNAILJOELITON_BARROS_SILVA.pdf.jpgJOELITON_BARROS_SILVA.pdf.jpgGenerated Thumbnailimage/jpeg1284https://ri.ufs.br/jspui/bitstream/riufs/18655/4/JOELITON_BARROS_SILVA.pdf.jpg0841133da4a2037d5eddff939c2a63baMD54riufs/186552023-11-16 08:00:53.919oai:ufs.br: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Repositório InstitucionalPUBhttps://ri.ufs.br/oai/requestrepositorio@academico.ufs.bropendoar:2023-11-16T11:00:53Repositório Institucional da UFS - Universidade Federal de Sergipe (UFS)false |
dc.title.pt_BR.fl_str_mv |
Estudo de modelos de spins com interação Dzyaloshinskii-Moriya |
title |
Estudo de modelos de spins com interação Dzyaloshinskii-Moriya |
spellingShingle |
Estudo de modelos de spins com interação Dzyaloshinskii-Moriya Silva, Joeliton Barros da Interação Dzyaloshinskii-Moriya Transições de fases Modelo de Heisenberg Campo aleatório Ponto tricrítico Dzyaloshinskii-Moriya interaction Phase transitions Heisenberg model Random field Tricritical point CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Estudo de modelos de spins com interação Dzyaloshinskii-Moriya |
title_full |
Estudo de modelos de spins com interação Dzyaloshinskii-Moriya |
title_fullStr |
Estudo de modelos de spins com interação Dzyaloshinskii-Moriya |
title_full_unstemmed |
Estudo de modelos de spins com interação Dzyaloshinskii-Moriya |
title_sort |
Estudo de modelos de spins com interação Dzyaloshinskii-Moriya |
author |
Silva, Joeliton Barros da |
author_facet |
Silva, Joeliton Barros da |
author_role |
author |
dc.contributor.author.fl_str_mv |
Silva, Joeliton Barros da |
dc.contributor.advisor1.fl_str_mv |
Albuquerque, Douglas Ferreira de |
contributor_str_mv |
Albuquerque, Douglas Ferreira de |
dc.subject.por.fl_str_mv |
Interação Dzyaloshinskii-Moriya Transições de fases Modelo de Heisenberg Campo aleatório Ponto tricrítico Dzyaloshinskii-Moriya interaction Phase transitions Heisenberg model Random field Tricritical point |
topic |
Interação Dzyaloshinskii-Moriya Transições de fases Modelo de Heisenberg Campo aleatório Ponto tricrítico Dzyaloshinskii-Moriya interaction Phase transitions Heisenberg model Random field Tricritical point CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::FISICA |
description |
The critical properties of systems that exhibit magnetism have been the subject of intense research over the years. The study of the critical behavior of many magnetic, insulating and anisotropic materials can be approached through Ising and Heisenberg models, for exemple. Taking into account anisotropic effects in spin models usually results in the presence of tricritical behavior in the phase diagram. In particular, the Dzyaloshinskii-Moriya interaction consists of an important type of anisotropy, which has attracted attention over the last decades, playing an important role in the description of some classes of insulators, as well as in the study of phenomena involving chirality, among others. The presence of disorder in the models, introduced through random variables governed by probability distributions, also results in a change in critical behavior in relation to pure systems. In this thesis, the ferromagnetic anisotropic Heisenberg model with Dzyaloshinskii-Moriya interaction is studied in spin-3/2 and spin-2 versions within the pair approximation. The formalism can be applied to different types of lattice. However, the results presented here deal in detail with the case of the simple cubic lattice (q = 6). The phase diagrams and magnetic properties reveal the existence of tricritical points and first-order phase transitions. For the spin-1 model, cases involving the disorder generated from the inclusion of a random field are treated. In addition, some results with the application of the effective field theory, as well as the antiferromagnetic model, are discussed. |
publishDate |
2022 |
dc.date.issued.fl_str_mv |
2022-09-21 |
dc.date.accessioned.fl_str_mv |
2023-11-14T20:59:03Z |
dc.date.available.fl_str_mv |
2023-11-14T20:59:03Z |
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info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
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doctoralThesis |
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publishedVersion |
dc.identifier.citation.fl_str_mv |
SILVA, Joeliton Barros da. Estudo de modelos de spins com interação Dzyaloshinskii-Moriya. 2022. 103 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2022. |
dc.identifier.uri.fl_str_mv |
https://ri.ufs.br/jspui/handle/riufs/18655 |
identifier_str_mv |
SILVA, Joeliton Barros da. Estudo de modelos de spins com interação Dzyaloshinskii-Moriya. 2022. 103 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2022. |
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https://ri.ufs.br/jspui/handle/riufs/18655 |
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Pós-Graduação em Física |
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Universidade Federal de Sergipe (UFS) |
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