Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn
Autor(a) principal: | |
---|---|
Data de Publicação: | 2013 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da Universidade Federal do Espírito Santo (riUfes) |
Texto Completo: | http://repositorio.ufes.br/handle/10/7484 |
Resumo: | In the present work, a systematic investigation, through structural and magnetic characterizations, is discussed regarding the influence of the crystallographic texture on the Exchange Spring observed in the NiFe/IrMn/Co trilayer deposited at room temperature with Magnetron Sputtering technique. Using X-ray diffraction, it was shown that NiFe, IrMn and Co layers have texture oriented fcc [111], when Ta seed layer deposited, and there was no of other types of orientations. For samples grown on Cu seed layer, beyond majority [111]-fcc, types of [200] and [220] orientations are also present in the diffraction patterns of the NiFe/IrMn/Co heterostructures. From X-ray reflectivity, it was determined that the Cu-system has much high Si/Cu interface roughness (Si/Cu, rms = 2.8 nm) than that of Ta (Si/Ta, rms = 0.2 nm). Combining results from the combination of DC magnetization and ferromagnetic resonance techniques, performed at room temperature, it is provided a planar magnetic anisotropy and an understanding of the Exchange Bias (unidirectional exchange coupling at the NiFe/IrMn and IrMn/Co interfaces) and the Exchange Spring effects in NiFe/IrMn/Co heterostructures. DC magnetization data suggest that the Exchange Spring exists before the field cooling protocol (unidirectional anisotropy induction). The Exchange Spring phenomenon (consequently the IrMn spins structure) was shown to be strongly dependent on the degree of [111] texture in the IrMn layer, which is, in turn, dependent on the seed layer (Cu or Ta) deposited on Si(100) substrate. It has also been demonstrated, a posteriori, that a field cooling of 10 Oe is sufficient to set the Exchange Bias effect on both interfaces (NiFe/IrMn and IrMn/Co). In addition, it was observed that the highest Exchange Bias field occurs when an unstressed L12 IrMn structure is stabilized at 6-8 nm IrMn thickness interval. Due to different degree of texture (interface roughness may also be present), it can be shown that exchange bias effect is distinct for Ta and Cu systems. For the systems where unidirectional anisotropy is set, it has been demonstrated that for increasing IrMn thickness (from 5 up to 30 nm), the magnetic coupling angle between NiFe and Co magnetizations increases for the Cu-system, while it is reduced in the Ta-system. These results were explained considering: (i) the measured different anisotropies of the Co and IrMn layers induced by the [111] texture and (ii) distinct Exchange Bias field in NiFe/IrMn and IrMn/Co interfaces in both systems. It was shown that the coupling angle is strongly correlated by both Exchange Bias and Exchange Spring effects. Through resonant magnetic scattering measurements found a presence of reversible non-compensated under the action of magnetic field for both systems with unidirectional anisotropy (clearer effect for the Cu-system). Furthermore hysteresis loops through element selective obtained by this technique proved the presence of Exchange Spring effect in Cu system, even prior to applying cooling field. |
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Nascimento, Valberto PedruzziCaetano, Edson PassamaniMerino, Isabel Liz CastroGarcia, FlávioBaggio-Saitovitch, Elisa MariaLarica, CarlosFernandes, Antonio Alberto Ribeiro2018-08-01T22:30:00Z2018-08-012018-08-01T22:30:00Z2013-07-19In the present work, a systematic investigation, through structural and magnetic characterizations, is discussed regarding the influence of the crystallographic texture on the Exchange Spring observed in the NiFe/IrMn/Co trilayer deposited at room temperature with Magnetron Sputtering technique. Using X-ray diffraction, it was shown that NiFe, IrMn and Co layers have texture oriented fcc [111], when Ta seed layer deposited, and there was no of other types of orientations. For samples grown on Cu seed layer, beyond majority [111]-fcc, types of [200] and [220] orientations are also present in the diffraction patterns of the NiFe/IrMn/Co heterostructures. From X-ray reflectivity, it was determined that the Cu-system has much high Si/Cu interface roughness (Si/Cu, rms = 2.8 nm) than that of Ta (Si/Ta, rms = 0.2 nm). Combining results from the combination of DC magnetization and ferromagnetic resonance techniques, performed at room temperature, it is provided a planar magnetic anisotropy and an understanding of the Exchange Bias (unidirectional exchange coupling at the NiFe/IrMn and IrMn/Co interfaces) and the Exchange Spring effects in NiFe/IrMn/Co heterostructures. DC magnetization data suggest that the Exchange Spring exists before the field cooling protocol (unidirectional anisotropy induction). The Exchange Spring phenomenon (consequently the IrMn spins structure) was shown to be strongly dependent on the degree of [111] texture in the IrMn layer, which is, in turn, dependent on the seed layer (Cu or Ta) deposited on Si(100) substrate. It has also been demonstrated, a posteriori, that a field cooling of 10 Oe is sufficient to set the Exchange Bias effect on both interfaces (NiFe/IrMn and IrMn/Co). In addition, it was observed that the highest Exchange Bias field occurs when an unstressed L12 IrMn structure is stabilized at 6-8 nm IrMn thickness interval. Due to different degree of texture (interface roughness may also be present), it can be shown that exchange bias effect is distinct for Ta and Cu systems. For the systems where unidirectional anisotropy is set, it has been demonstrated that for increasing IrMn thickness (from 5 up to 30 nm), the magnetic coupling angle between NiFe and Co magnetizations increases for the Cu-system, while it is reduced in the Ta-system. These results were explained considering: (i) the measured different anisotropies of the Co and IrMn layers induced by the [111] texture and (ii) distinct Exchange Bias field in NiFe/IrMn and IrMn/Co interfaces in both systems. It was shown that the coupling angle is strongly correlated by both Exchange Bias and Exchange Spring effects. Through resonant magnetic scattering measurements found a presence of reversible non-compensated under the action of magnetic field for both systems with unidirectional anisotropy (clearer effect for the Cu-system). Furthermore hysteresis loops through element selective obtained by this technique proved the presence of Exchange Spring effect in Cu system, even prior to applying cooling field.Apresenta-se, no presente trabalho, uma investigação sistemática, através da caracterização estrutural e magnética, da infuência da textura cristalográfica sobre o efeito de Exchange Spring presente nas tricamadas NiFe/IrMn/Co depositadas, à temperatura ambiente, pelo método de Magnetron Sputtering. Usando a difração de Raios-X, demonstrou-se que as camadas de NiFe, IrMn e Co estão texturizadas com orientação [111]-fcc quando a deposição ocorre sobre a camada semente de Ta, não havendo constatação de outros tipos de orientações. Para as amostras crescidas sobre a camada semente de Cu, além da orientação majoritária [111]-fcc, orientações do tipo [200] e [220] encontram-se também presentes nos difratogramas das heteroestruturas NiFe/IrMn/Co. Deste modo, constata-se que o sistema com Ta possui um grau de textura [111] maior do que aquele do sistema com Cu. Da análise das curvas de difração de Raios-X em ângulos rasantes (refletividade) dos sistemas com Cu e Ta, verifica-se que o sistema com Cu possui uma elevada rugosidade na interface Si/Cu (2,8 nm), quando comparada com aquela da interface Si/Ta (0,2 nm) do sistema com Ta. A combinação das técnicas de magnetização DC e ressonância ferromagnética, à temperatura ambiente, nos proporcionou estudar a anisotropia magnética planar e os efeitos conjugados de Exchange Bias (acoplamento de troca unidirecional nas interfaces NiFe/IrMn e IrMn/Co) e Exchange Spring nas heteroestruturas NiFe/IrMn/Co. Os resultados de magnetização DC sugerem que o efeito de Exchange Spring existe mesmo antes da aplicação de um resfriamento com campo magnético (indução de anisotropia unidirecional). O fenômeno de Exchange Spring (consequentemente a estrutura de spins do IrMn) se mostrou fortemente dependente do grau de textura [111] da camada de IrMn que, por sua vez, é dependente da camada semente (Cu ou Ta) depositada sobre o substrato de Si(100). Verificou-se, a posteriori, que um campo magnético de resfriamento de 10 Oe (desde 400 K até 300 K) é suficiente para estabelecer o efeito de Exchange Bias em ambas as interfaces (NiFe/IrMn e IrMn/Co). Observou-se que os maiores valores do campo de Exchange Bias ocorrem quando se estabiliza a estrutura L12 do IrMn (intervalo 6-8 nm), a qual possui baixa tensão cristalográfica. Devido aos diferentes graus de textura (um efeito de rugosidade pode também estar presente), demonstra-se que o efeito de Exchange Bias da interface IrMn/Co é distinto para os sistemas com Ta e Cu. Para os sistemas com anisotropia unidirecional, comprovou-se que ao se aumentar a espessura da camada de IrMn (de 5 a 30 nm), o ângulo de acoplamento entre a camada de NiFe e a camada de Co aumentou no sistema com Cu e reduziu no sistema com Ta, apresentando comportamentos opostos. Explicaram-se estes resultados considerando: (i) diferentes anisotropias das camadas de Co e IrMn induzidas pelo grau de textura [111] e (ii) campos de Exchange Bias distintos nas interfaces NiFe/IrMn e IrMn/Co em ambos os sistemas. Comprovou-se que o ângulo de acoplamento encontra-se fortemente correlacionado com ambos os efeitos: Exchange Bias e Exchange Spring. Através de medidas de espalhamento magnético ressonante, constatou-se a presença de spins não-compensados reversíveis sob ação de campo magnético para ambos os sistemas com anisotropia unidirecional (efeito mais claro para o sistema com Cu). Além disso, através dos laços de histerese elemento seletivo obtidos por essa técnica, provou-se a presença do efeito de Exchange Spring no sistema com Cu, mesmo antes de se aplicar o resfriamento com campo magnético.TextMERINO, Isabel Liz Castro. Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: A Influência da Textura Cristalográfica da camada IrMn. 2013. 189 f. Tese (Doutorado em Física) – Universidade Federal do Espírito Santo, Vitória, 2013.http://repositorio.ufes.br/handle/10/7484porUniversidade Federal do Espírito SantoDoutorado em FísicaPrograma de Pós-Graduação em FísicaUFESBRCentro de Ciências ExatasMagnetic propertiesThin filmsAnisotropyMagnetic couplingPropriedades magnéticasFilmes finosAnisotropiaAcoplamento magnéticoFísica53Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMninfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)instname:Universidade Federal do Espírito Santo (UFES)instacron:UFESORIGINALIsabelLizCastroMerino-2013-trabalho.pdfapplication/pdf24470299http://repositorio.ufes.br/bitstreams/ce43acd0-1480-48f5-af1b-617412640810/downloadb2fd9bf97061153286bf599b7c21de10MD5110/74842024-06-28 18:06:27.112oai:repositorio.ufes.br:10/7484http://repositorio.ufes.brRepositório InstitucionalPUBhttp://repositorio.ufes.br/oai/requestopendoar:21082024-06-28T18:06:27Repositório Institucional da Universidade Federal do Espírito Santo (riUfes) - Universidade Federal do Espírito Santo (UFES)false |
dc.title.none.fl_str_mv |
Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn |
title |
Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn |
spellingShingle |
Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn Merino, Isabel Liz Castro Magnetic properties Thin films Anisotropy Magnetic coupling Propriedades magnéticas Filmes finos Anisotropia Acoplamento magnético Física 53 |
title_short |
Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn |
title_full |
Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn |
title_fullStr |
Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn |
title_full_unstemmed |
Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn |
title_sort |
Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: a Influência da Textura Cristalográfica da camada IrMn |
author |
Merino, Isabel Liz Castro |
author_facet |
Merino, Isabel Liz Castro |
author_role |
author |
dc.contributor.advisor-co1.fl_str_mv |
Nascimento, Valberto Pedruzzi |
dc.contributor.advisor1.fl_str_mv |
Caetano, Edson Passamani |
dc.contributor.author.fl_str_mv |
Merino, Isabel Liz Castro |
dc.contributor.referee1.fl_str_mv |
Garcia, Flávio |
dc.contributor.referee2.fl_str_mv |
Baggio-Saitovitch, Elisa Maria |
dc.contributor.referee3.fl_str_mv |
Larica, Carlos |
dc.contributor.referee4.fl_str_mv |
Fernandes, Antonio Alberto Ribeiro |
contributor_str_mv |
Nascimento, Valberto Pedruzzi Caetano, Edson Passamani Garcia, Flávio Baggio-Saitovitch, Elisa Maria Larica, Carlos Fernandes, Antonio Alberto Ribeiro |
dc.subject.eng.fl_str_mv |
Magnetic properties Thin films Anisotropy Magnetic coupling |
topic |
Magnetic properties Thin films Anisotropy Magnetic coupling Propriedades magnéticas Filmes finos Anisotropia Acoplamento magnético Física 53 |
dc.subject.por.fl_str_mv |
Propriedades magnéticas Filmes finos Anisotropia Acoplamento magnético |
dc.subject.cnpq.fl_str_mv |
Física |
dc.subject.udc.none.fl_str_mv |
53 |
description |
In the present work, a systematic investigation, through structural and magnetic characterizations, is discussed regarding the influence of the crystallographic texture on the Exchange Spring observed in the NiFe/IrMn/Co trilayer deposited at room temperature with Magnetron Sputtering technique. Using X-ray diffraction, it was shown that NiFe, IrMn and Co layers have texture oriented fcc [111], when Ta seed layer deposited, and there was no of other types of orientations. For samples grown on Cu seed layer, beyond majority [111]-fcc, types of [200] and [220] orientations are also present in the diffraction patterns of the NiFe/IrMn/Co heterostructures. From X-ray reflectivity, it was determined that the Cu-system has much high Si/Cu interface roughness (Si/Cu, rms = 2.8 nm) than that of Ta (Si/Ta, rms = 0.2 nm). Combining results from the combination of DC magnetization and ferromagnetic resonance techniques, performed at room temperature, it is provided a planar magnetic anisotropy and an understanding of the Exchange Bias (unidirectional exchange coupling at the NiFe/IrMn and IrMn/Co interfaces) and the Exchange Spring effects in NiFe/IrMn/Co heterostructures. DC magnetization data suggest that the Exchange Spring exists before the field cooling protocol (unidirectional anisotropy induction). The Exchange Spring phenomenon (consequently the IrMn spins structure) was shown to be strongly dependent on the degree of [111] texture in the IrMn layer, which is, in turn, dependent on the seed layer (Cu or Ta) deposited on Si(100) substrate. It has also been demonstrated, a posteriori, that a field cooling of 10 Oe is sufficient to set the Exchange Bias effect on both interfaces (NiFe/IrMn and IrMn/Co). In addition, it was observed that the highest Exchange Bias field occurs when an unstressed L12 IrMn structure is stabilized at 6-8 nm IrMn thickness interval. Due to different degree of texture (interface roughness may also be present), it can be shown that exchange bias effect is distinct for Ta and Cu systems. For the systems where unidirectional anisotropy is set, it has been demonstrated that for increasing IrMn thickness (from 5 up to 30 nm), the magnetic coupling angle between NiFe and Co magnetizations increases for the Cu-system, while it is reduced in the Ta-system. These results were explained considering: (i) the measured different anisotropies of the Co and IrMn layers induced by the [111] texture and (ii) distinct Exchange Bias field in NiFe/IrMn and IrMn/Co interfaces in both systems. It was shown that the coupling angle is strongly correlated by both Exchange Bias and Exchange Spring effects. Through resonant magnetic scattering measurements found a presence of reversible non-compensated under the action of magnetic field for both systems with unidirectional anisotropy (clearer effect for the Cu-system). Furthermore hysteresis loops through element selective obtained by this technique proved the presence of Exchange Spring effect in Cu system, even prior to applying cooling field. |
publishDate |
2013 |
dc.date.issued.fl_str_mv |
2013-07-19 |
dc.date.accessioned.fl_str_mv |
2018-08-01T22:30:00Z |
dc.date.available.fl_str_mv |
2018-08-01 2018-08-01T22:30:00Z |
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 |
MERINO, Isabel Liz Castro. Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: A Influência da Textura Cristalográfica da camada IrMn. 2013. 189 f. Tese (Doutorado em Física) – Universidade Federal do Espírito Santo, Vitória, 2013. |
dc.identifier.uri.fl_str_mv |
http://repositorio.ufes.br/handle/10/7484 |
identifier_str_mv |
MERINO, Isabel Liz Castro. Fenômenos de Exchange Bias e Exchange Spring em Tricamadas NiFe/IrMn/Co: A Influência da Textura Cristalográfica da camada IrMn. 2013. 189 f. Tese (Doutorado em Física) – Universidade Federal do Espírito Santo, Vitória, 2013. |
url |
http://repositorio.ufes.br/handle/10/7484 |
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por |
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openAccess |
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Text |
dc.publisher.none.fl_str_mv |
Universidade Federal do Espírito Santo Doutorado em Física |
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Programa de Pós-Graduação em Física |
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UFES |
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BR |
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Centro de Ciências Exatas |
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Universidade Federal do Espírito Santo Doutorado em Física |
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