Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras
Autor(a) principal: | |
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Data de Publicação: | 2017 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFS |
Texto Completo: | http://ri.ufs.br/jspui/handle/riufs/9009 |
Resumo: | In this work we concentrate our efforts to obtain an algebraic relation capable of connecting the magnetic component of the caloric magneto potential, the magnetic entropy variation with the magnetic resistivity variation of the anisotropic magneto caloric compounds of the series RAl2, (R: rare earth). For this purpose, we use the single ion model, considering the approximation of the molecular field based on the interaction of long-range cooperative exchange to represent the magnetic interactions present in these compounds, through the Hamiltonian model. While the study of the resistive properties was carried out based on the dispersive dipole interaction between the conducting electrons and 4f located. This analytical and self consistent process results in ()-T e ()-T curves, which are compared to experimental data available in the literature. The comparison between these quantities, for the different crystallographic directions of the monocrystalline compounds RAl2, lacks the inclusion of a correlation factor that involves a power relation (T/Tc)m, whose exponent varies according to the thermal conditions and anisotropic. That is, for the compound HoAl2, for example the validity of the expression −=− is guaranteed by using the index m = 0.1 for region 0<T<Tc where the spin reorientation occurs, and for region that happens Tc the index m = 0.0 (direct ratio) must be used. This procedure was also used to describe the properties of the compounds TmAl2, DyAl2 and NdAl2, providing valuable information about the relationship between the variation of magnetic entropy and the variation of magnetic resistivity. |
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Souza, Marcos Vinicios dePlaza, Edison Jesus Ramirez2018-09-25T15:57:00Z2018-09-25T15:57:00Z2017-03-15SOUZA, Marcos Vinicios de. Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras. 2017. 60 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, SE, 2017.http://ri.ufs.br/jspui/handle/riufs/9009In this work we concentrate our efforts to obtain an algebraic relation capable of connecting the magnetic component of the caloric magneto potential, the magnetic entropy variation with the magnetic resistivity variation of the anisotropic magneto caloric compounds of the series RAl2, (R: rare earth). For this purpose, we use the single ion model, considering the approximation of the molecular field based on the interaction of long-range cooperative exchange to represent the magnetic interactions present in these compounds, through the Hamiltonian model. While the study of the resistive properties was carried out based on the dispersive dipole interaction between the conducting electrons and 4f located. This analytical and self consistent process results in ()-T e ()-T curves, which are compared to experimental data available in the literature. The comparison between these quantities, for the different crystallographic directions of the monocrystalline compounds RAl2, lacks the inclusion of a correlation factor that involves a power relation (T/Tc)m, whose exponent varies according to the thermal conditions and anisotropic. That is, for the compound HoAl2, for example the validity of the expression −=− is guaranteed by using the index m = 0.1 for region 0<T<Tc where the spin reorientation occurs, and for region that happens Tc the index m = 0.0 (direct ratio) must be used. This procedure was also used to describe the properties of the compounds TmAl2, DyAl2 and NdAl2, providing valuable information about the relationship between the variation of magnetic entropy and the variation of magnetic resistivity.Neste trabalho concentramos nossos esforços para a obtenção de uma relação algébrica capaz de conectar a componente magnética do potencial magneto calórico, variação de entropia magnética com a variação de resistividade magnética dos compostos magneto calóricos anisotrópicos integrantes da série RAl2, (R: terra rara). Para este fim, utilizamos o modelo de único íon, considerando a aproximação do campo molecular baseada na interação de troca cooperativa de longo alcance para representar as interações magnéticas presentes nestes compostos, através do hamiltoniano modelo. Enquanto o estudo das propriedades resistivas foi realizado com base na interação dispersiva dipolar entre os elétrons de condução e 4f localizados. Este processo analítico e auto consistente resulta em curvas de ()-T e ()-T, que são comparadas a dados experimentais disponíveis na literatura. Já a comparação entre essas grandezas, para as diferentes direções cristalográficas dos compostos monocristalinos RAl2, carece da inclusão de um fator de correlação que envolve uma relação de potência (T/Tc)m, cujo expoente varia de acordo com as condições térmica e anisotrópica. Isto é, para o composto HoAl2, por exemplo a validade da expressão −=−(TTc)m é garantida com a utilização do índice m=0.1 para região 0<T<Tc onde ocorre a reorientação de spin, e para região que sucede Tc o índice m=0.0 (relação direta) deve ser utilizado. Este procedimento também foi utilizado para descrever as propriedades dos compostos TmAl2, DyAl2 e NdAl2, fornecendo informações valiosas sobre a relação existente entre a variação de entropia magnética com a variação de resistividade magnética.São Cristóvão, SEporMagnetismoPropriedades magnetotérmicasPropriedades de transporteIntermetálicosTerras rarasCIENCIAS EXATAS E DA TERRA::FISICAEstudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras rarasinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisPós-Graduação em FísicaUniversidade Federal de Sergipereponame:Repositório Institucional da UFSinstname:Universidade Federal de Sergipe (UFS)instacron:UFSinfo:eu-repo/semantics/openAccessTEXTMARCOS_VINICIOS_SOUZA.pdf.txtMARCOS_VINICIOS_SOUZA.pdf.txtExtracted texttext/plain109841https://ri.ufs.br/jspui/bitstream/riufs/9009/3/MARCOS_VINICIOS_SOUZA.pdf.txtbf741f3770e7d03088d7af17e2cf8908MD53THUMBNAILMARCOS_VINICIOS_SOUZA.pdf.jpgMARCOS_VINICIOS_SOUZA.pdf.jpgGenerated Thumbnailimage/jpeg1213https://ri.ufs.br/jspui/bitstream/riufs/9009/4/MARCOS_VINICIOS_SOUZA.pdf.jpg28b8a15963f93616cb3e8a91291f4545MD54LICENSElicense.txtlicense.txttext/plain; charset=utf-81475https://ri.ufs.br/jspui/bitstream/riufs/9009/1/license.txt098cbbf65c2c15e1fb2e49c5d306a44cMD51ORIGINALMARCOS_VINICIOS_SOUZA.pdfMARCOS_VINICIOS_SOUZA.pdfapplication/pdf2521765https://ri.ufs.br/jspui/bitstream/riufs/9009/2/MARCOS_VINICIOS_SOUZA.pdfe97e423982fe8d68823decbfe4e0d8e1MD52riufs/90092018-10-16 14:29:28.184oai:ufs.br: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Repositório InstitucionalPUBhttps://ri.ufs.br/oai/requestrepositorio@academico.ufs.bropendoar:2018-10-16T17:29:28Repositório Institucional da UFS - Universidade Federal de Sergipe (UFS)false |
dc.title.pt_BR.fl_str_mv |
Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras |
title |
Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras |
spellingShingle |
Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras Souza, Marcos Vinicios de Magnetismo Propriedades magnetotérmicas Propriedades de transporte Intermetálicos Terras raras CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras |
title_full |
Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras |
title_fullStr |
Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras |
title_full_unstemmed |
Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras |
title_sort |
Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras |
author |
Souza, Marcos Vinicios de |
author_facet |
Souza, Marcos Vinicios de |
author_role |
author |
dc.contributor.author.fl_str_mv |
Souza, Marcos Vinicios de |
dc.contributor.advisor1.fl_str_mv |
Plaza, Edison Jesus Ramirez |
contributor_str_mv |
Plaza, Edison Jesus Ramirez |
dc.subject.por.fl_str_mv |
Magnetismo Propriedades magnetotérmicas Propriedades de transporte Intermetálicos Terras raras |
topic |
Magnetismo Propriedades magnetotérmicas Propriedades de transporte Intermetálicos Terras raras CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::FISICA |
description |
In this work we concentrate our efforts to obtain an algebraic relation capable of connecting the magnetic component of the caloric magneto potential, the magnetic entropy variation with the magnetic resistivity variation of the anisotropic magneto caloric compounds of the series RAl2, (R: rare earth). For this purpose, we use the single ion model, considering the approximation of the molecular field based on the interaction of long-range cooperative exchange to represent the magnetic interactions present in these compounds, through the Hamiltonian model. While the study of the resistive properties was carried out based on the dispersive dipole interaction between the conducting electrons and 4f located. This analytical and self consistent process results in ()-T e ()-T curves, which are compared to experimental data available in the literature. The comparison between these quantities, for the different crystallographic directions of the monocrystalline compounds RAl2, lacks the inclusion of a correlation factor that involves a power relation (T/Tc)m, whose exponent varies according to the thermal conditions and anisotropic. That is, for the compound HoAl2, for example the validity of the expression −=− is guaranteed by using the index m = 0.1 for region 0<T<Tc where the spin reorientation occurs, and for region that happens Tc the index m = 0.0 (direct ratio) must be used. This procedure was also used to describe the properties of the compounds TmAl2, DyAl2 and NdAl2, providing valuable information about the relationship between the variation of magnetic entropy and the variation of magnetic resistivity. |
publishDate |
2017 |
dc.date.issued.fl_str_mv |
2017-03-15 |
dc.date.accessioned.fl_str_mv |
2018-09-25T15:57:00Z |
dc.date.available.fl_str_mv |
2018-09-25T15:57:00Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/doctoralThesis |
format |
doctoralThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
SOUZA, Marcos Vinicios de. Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras. 2017. 60 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, SE, 2017. |
dc.identifier.uri.fl_str_mv |
http://ri.ufs.br/jspui/handle/riufs/9009 |
identifier_str_mv |
SOUZA, Marcos Vinicios de. Estudo das propriedades magnetotérmicas e de transporte em intermetálicos contendo terras raras. 2017. 60 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, SE, 2017. |
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http://ri.ufs.br/jspui/handle/riufs/9009 |
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por |
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por |
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Pós-Graduação em Física |
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Universidade Federal de Sergipe |
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