Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias

Detalhes bibliográficos
Autor(a) principal: Rigue, Josué Neroti
Data de Publicação: 2014
Tipo de documento: Tese
Idioma: por
Título da fonte: Manancial - Repositório Digital da UFSM
dARK ID: ark:/26339/001300000txj3
Texto Completo: http://repositorio.ufsm.br/handle/1/3924
Resumo: The exchange bias (EB) phenomen occurs due to the coupling between ferromagnetic and antiferromagnetic material and the main characteristics are the rise of unidirectional anisotropy and the rotational hysteresis in torque curves. In this work we have investigated how the unidirectional anisotropy and the rotational hysteresis are influenced by the change of some characteristics in thin films samples. Among these are the stacking of layers, the roughness at the interface between the two materials, the difference in the ferromagnetic layer thickness and the difference between the antiferromagnetic materials. The study was made by using magnetic torque measurements which were interpreted using a granular model for the EB. The parameters obtained from the fitting of the model to the torque curves has also permitted to reproduce data obtained by different magnetic techniques, especially in samples where the unidirectional anisotropy is greater than the uniaxial anisotropy. In NiFe=IrMn samples, the unidirectional anisotropy is favored by stacking layers, by increasing of the interfacial roughness and by the decrease of the ferromagnetic layer thickness, while the rotational hysteresis is substantially increased as the interfacial roughness increases. For the NiFe=FeMn sample the highest values of unidirectional anisotropy and rotational hysteresis were found, as well as a dependence of these parameters with the measuring magnetic field.
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spelling Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange biasStudy of unidirectional anisotropy and rotational hysteresis in exchange bias systemsExchange biasAnisotropia unidirecionalHisterese rotacionalExchange biasUnidirectional anisotropyRotational hysteresisCNPQ::CIENCIAS EXATAS E DA TERRA::FISICAThe exchange bias (EB) phenomen occurs due to the coupling between ferromagnetic and antiferromagnetic material and the main characteristics are the rise of unidirectional anisotropy and the rotational hysteresis in torque curves. In this work we have investigated how the unidirectional anisotropy and the rotational hysteresis are influenced by the change of some characteristics in thin films samples. Among these are the stacking of layers, the roughness at the interface between the two materials, the difference in the ferromagnetic layer thickness and the difference between the antiferromagnetic materials. The study was made by using magnetic torque measurements which were interpreted using a granular model for the EB. The parameters obtained from the fitting of the model to the torque curves has also permitted to reproduce data obtained by different magnetic techniques, especially in samples where the unidirectional anisotropy is greater than the uniaxial anisotropy. In NiFe=IrMn samples, the unidirectional anisotropy is favored by stacking layers, by increasing of the interfacial roughness and by the decrease of the ferromagnetic layer thickness, while the rotational hysteresis is substantially increased as the interfacial roughness increases. For the NiFe=FeMn sample the highest values of unidirectional anisotropy and rotational hysteresis were found, as well as a dependence of these parameters with the measuring magnetic field.Conselho Nacional de Desenvolvimento Científico e TecnológicoO fenômeno de "exchange bias" (EB) ocorre quando um material ferromagnético está acoplado a um material antiferromagnético e apresenta como características principais o surgimento de uma anisotropia unidirecional e a histerese rotacional em curvas de torque. Nesse trabalho foi investigado como a anisotropia unidirecional e a histerese rotacional são influenciadas pela mudança de algumas características em amostras na forma de filme finos. Entre essas características estão o empilhamento de camadas, a rugosidade na interface entre os dois materiais, a diferença na espessura da camada ferromagnética e a diferença entre os materiais antiferromagnéticos. O estudo foi realizado através de medidas de magnetometria de torque nas amostras, as quais foram interpretadas usando um modelo granular para o EB. Os parâmetros resultantes do ajuste do modelo às curvas de torque permitiram também reproduzir dados obtidos por outras técnicas de caracterização magnética, sobretudo em amostras que apresentam a anisotropia unidirecional maior do que a anisotropia uniaxial. Em amostras de NiFe=IrMn, a predominância da anisotropia unidirecional é favorecida pelo empilhamento de camadas, pelo aumento da rugosidade interfacial e pela diminuição da espessura da camada ferromagnética, enquanto a histerese rotacional apresenta aumento significativo somente com o aumento da rugosidade. Em uma amostra de NiFe=FeMn foram encontrados valores maiores tanto para a anisotropia unidirecional quanto para a histerese rotacional, bem como uma dependência desses com o campo de medida.Universidade Federal de Santa MariaBRFísicaUFSMPrograma de Pós-Graduação em FísicaCarara, Marcos Andréhttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782774A7Sommer, Rubem Luishttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4785875E6Geshev, Julian Penkovhttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4796188E3Schelp, Luiz Fernandohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782843Y8Piquini, Paulo Cesarhttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782185U1Rigue, Josué Neroti2017-05-092017-05-092014-08-18info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfapplication/pdfRIGUE, Josué Neroti. Study of unidirectional anisotropy and rotational hysteresis in exchange bias systems. 2014. 152 f. Tese (Doutorado em Física) - Universidade Federal de Santa Maria, Santa Maria, 2014.http://repositorio.ufsm.br/handle/1/3924ark:/26339/001300000txj3porinfo:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSM2017-07-25T14:01:16Zoai:repositorio.ufsm.br:1/3924Biblioteca Digital de Teses e Dissertaçõeshttps://repositorio.ufsm.br/ONGhttps://repositorio.ufsm.br/oai/requestatendimento.sib@ufsm.br||tedebc@gmail.comopendoar:2017-07-25T14:01:16Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false
dc.title.none.fl_str_mv Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
Study of unidirectional anisotropy and rotational hysteresis in exchange bias systems
title Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
spellingShingle Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
Rigue, Josué Neroti
Exchange bias
Anisotropia unidirecional
Histerese rotacional
Exchange bias
Unidirectional anisotropy
Rotational hysteresis
CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
title_short Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
title_full Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
title_fullStr Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
title_full_unstemmed Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
title_sort Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
author Rigue, Josué Neroti
author_facet Rigue, Josué Neroti
author_role author
dc.contributor.none.fl_str_mv Carara, Marcos André
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782774A7
Sommer, Rubem Luis
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4785875E6
Geshev, Julian Penkov
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4796188E3
Schelp, Luiz Fernando
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782843Y8
Piquini, Paulo Cesar
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782185U1
dc.contributor.author.fl_str_mv Rigue, Josué Neroti
dc.subject.por.fl_str_mv Exchange bias
Anisotropia unidirecional
Histerese rotacional
Exchange bias
Unidirectional anisotropy
Rotational hysteresis
CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
topic Exchange bias
Anisotropia unidirecional
Histerese rotacional
Exchange bias
Unidirectional anisotropy
Rotational hysteresis
CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA
description The exchange bias (EB) phenomen occurs due to the coupling between ferromagnetic and antiferromagnetic material and the main characteristics are the rise of unidirectional anisotropy and the rotational hysteresis in torque curves. In this work we have investigated how the unidirectional anisotropy and the rotational hysteresis are influenced by the change of some characteristics in thin films samples. Among these are the stacking of layers, the roughness at the interface between the two materials, the difference in the ferromagnetic layer thickness and the difference between the antiferromagnetic materials. The study was made by using magnetic torque measurements which were interpreted using a granular model for the EB. The parameters obtained from the fitting of the model to the torque curves has also permitted to reproduce data obtained by different magnetic techniques, especially in samples where the unidirectional anisotropy is greater than the uniaxial anisotropy. In NiFe=IrMn samples, the unidirectional anisotropy is favored by stacking layers, by increasing of the interfacial roughness and by the decrease of the ferromagnetic layer thickness, while the rotational hysteresis is substantially increased as the interfacial roughness increases. For the NiFe=FeMn sample the highest values of unidirectional anisotropy and rotational hysteresis were found, as well as a dependence of these parameters with the measuring magnetic field.
publishDate 2014
dc.date.none.fl_str_mv 2014-08-18
2017-05-09
2017-05-09
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.uri.fl_str_mv RIGUE, Josué Neroti. Study of unidirectional anisotropy and rotational hysteresis in exchange bias systems. 2014. 152 f. Tese (Doutorado em Física) - Universidade Federal de Santa Maria, Santa Maria, 2014.
http://repositorio.ufsm.br/handle/1/3924
dc.identifier.dark.fl_str_mv ark:/26339/001300000txj3
identifier_str_mv RIGUE, Josué Neroti. Study of unidirectional anisotropy and rotational hysteresis in exchange bias systems. 2014. 152 f. Tese (Doutorado em Física) - Universidade Federal de Santa Maria, Santa Maria, 2014.
ark:/26339/001300000txj3
url http://repositorio.ufsm.br/handle/1/3924
dc.language.iso.fl_str_mv por
language por
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv Universidade Federal de Santa Maria
BR
Física
UFSM
Programa de Pós-Graduação em Física
publisher.none.fl_str_mv Universidade Federal de Santa Maria
BR
Física
UFSM
Programa de Pós-Graduação em Física
dc.source.none.fl_str_mv reponame:Manancial - Repositório Digital da UFSM
instname:Universidade Federal de Santa Maria (UFSM)
instacron:UFSM
instname_str Universidade Federal de Santa Maria (UFSM)
instacron_str UFSM
institution UFSM
reponame_str Manancial - Repositório Digital da UFSM
collection Manancial - Repositório Digital da UFSM
repository.name.fl_str_mv Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)
repository.mail.fl_str_mv atendimento.sib@ufsm.br||tedebc@gmail.com
_version_ 1815172398353219584