Estudo da anisotropia unidirecional e da histerese rotacional em sistemas com exchange bias
Autor(a) principal: | |
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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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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 |