Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica
Main Author: | |
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Publication Date: | 2015 |
Format: | Master thesis |
Language: | por |
Source: | Manancial - Repositório Digital da UFSM |
Download full: | http://repositorio.ufsm.br/handle/1/9252 |
Summary: | In this work a study of the exchange interaction between ferromagnetic (NiFe) and antiferromagnetic (IrMn) layers was done through structural, magnetic and electric characterization. NiFe/IrMn/Ta films were grown with different number of repetitions of this basic structure aiming to evaluate possible changes on the magnetic anisotropies presented by the samples. It was implanted in the Laboratório de Magnetismo e Materiais Magnéticos a system in order to measure the Anisotropic Magnetorresistance (AMR) as function of the applied field angle. The AMR consists in a change of the eletric resistance of a ferromagnetic material as function of the angle between the electric current and the magnetization of the material and, by this way, sensible to changes in the anisotropy presented by the samples. It is presented a simple model to calculate the AMR as function of the angle field and, by comparing with the experimental curves, to obtain the magnetic parameters who describe the system. In the model the equilibrium direction of the magnetization is obtained from the minimization of the free magnetic energy, which is given by the Zeeman, uniaxial, unidirectional and manetostatic energies. The AMR curves present an assymetry around 180 degrees when measured at fields below the bias one. According to the fittings, it was found that such assymetry can be due by a misalignment between the anisotropy axis (uniaxial and unidirectional) or by a misalignment between the measuring current and the easy magnetic axis of the samples. It was not observed, as expected, an expressive increase of the anisotropy dispersion of the uniaxial anisotropy with the increase of the number of trilayers. The same was observed with the bias and coercive fields. |
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2017-05-092017-05-092015-08-07SIQUEIRA, Junara Villanova de. Exchange bias in NiFe/IrMn/Ta multilayers: a study through Anisotropic magnetoresistance. 2015. 81 f. Dissertação (Mestrado em Física) - Universidade Federal de Santa Maria, Santa Maria, 2015.http://repositorio.ufsm.br/handle/1/9252In this work a study of the exchange interaction between ferromagnetic (NiFe) and antiferromagnetic (IrMn) layers was done through structural, magnetic and electric characterization. NiFe/IrMn/Ta films were grown with different number of repetitions of this basic structure aiming to evaluate possible changes on the magnetic anisotropies presented by the samples. It was implanted in the Laboratório de Magnetismo e Materiais Magnéticos a system in order to measure the Anisotropic Magnetorresistance (AMR) as function of the applied field angle. The AMR consists in a change of the eletric resistance of a ferromagnetic material as function of the angle between the electric current and the magnetization of the material and, by this way, sensible to changes in the anisotropy presented by the samples. It is presented a simple model to calculate the AMR as function of the angle field and, by comparing with the experimental curves, to obtain the magnetic parameters who describe the system. In the model the equilibrium direction of the magnetization is obtained from the minimization of the free magnetic energy, which is given by the Zeeman, uniaxial, unidirectional and manetostatic energies. The AMR curves present an assymetry around 180 degrees when measured at fields below the bias one. According to the fittings, it was found that such assymetry can be due by a misalignment between the anisotropy axis (uniaxial and unidirectional) or by a misalignment between the measuring current and the easy magnetic axis of the samples. It was not observed, as expected, an expressive increase of the anisotropy dispersion of the uniaxial anisotropy with the increase of the number of trilayers. The same was observed with the bias and coercive fields.Neste trabalho, o estudo da interação de troca entre as camadas ferromagnética (NiFe) e antiferromagnética (IrMn) em multicamadas foi realizado através da caracterização estrutural, magnética e de transporte elétrico. Foram crescidos filmes de NiFe/IrMn/Ta com diferentes números de repetições dessa estrutura básica com o objetivo de avaliar as possíveis modificações nas anisotropias apresentadas pelas amostras. Foi implantado no Laboratório de Magnetismo e Materiais Magnéticos (LMMM) um sistema para medidas de Magnetorresistência Anisotrópica (AMR) em função do ângulo de aplicação do campo. A AMR consiste na variação da resistência elétrica e a magnetização do material e, portanto, sensível as modificações de anisotropia nas amostras. É apresentado um modelo simples para calcular as curvas de AMR em função do ângulo do campo e, na comparação com as curvas experimentais obter os parâmetros magnéticos que descrevem o sistema. No modelo, a direção de equilíbrio da magnetização é obtida a partir da minimização da energia livre magnética, que por sua vez é dada pela soma da energia Zeeman, uniaxial, unidirecional e magnetostática. As curvas de AMR apresentam uma assimetria em torno de 180 graus quando medidas em valores de campo menores que o campo de Bias. De acordo com os ajustes, foi verificado que esta assimetria pode ser causada tanto por um desalinhamento entre os eixos de anisotropias (uniaxial ou unidirecional) como por um desalinhamento entre o eixo da corrente de medição e o eixo de fácil magnetização da amostra. Não foi observado, conforme esperado, um aumento expressivo na dispersão da anisotropia uniaxial com o aumento do número de repetições das tricamadas. O mesmo ocorrendo com os valores dos campos de Bias e coercivo.Coordenação de Aperfeiçoamento de Pessoal de Nível Superiorapplication/pdfporUniversidade Federal de Santa MariaPrograma de Pós-Graduação em FísicaUFSMBRFísicaMagnetorresistência anisotrópicaExchange biasAnisotropiaAnsotropic magnetoresistanceExchange biasAnisotropyCNPQ::CIENCIAS EXATAS E DA TERRA::FISICAExchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópicaExchange bias in NiFe/IrMn/Ta multilayers: a study through Anisotropic magnetoresistanceinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesisCarara, Marcos Andréhttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782774A7Sossmeier, Kelly Daianehttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4771352J2Calegari, Eleonir Joãohttp://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4765559T0http://lattes.cnpq.br/6247242479912175Siqueira, Junara Villanova de100500000006400500300300300a8bf0e5b-f6aa-4bdc-8cf7-3957f5757509daff5b6a-a8d4-4a4b-96e3-02b16f3af37a04b85944-dc0c-4c17-a690-01057280b523b692b3df-83b9-408c-8d18-796e1635d63finfo:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSMORIGINALSIQUEIRA, JUNARA VILLANOVA DE.pdfapplication/pdf6794209http://repositorio.ufsm.br/bitstream/1/9252/1/SIQUEIRA%2c%20JUNARA%20VILLANOVA%20DE.pdf07324c13c9313635ffe8c9e5ddf14119MD51TEXTSIQUEIRA, JUNARA VILLANOVA DE.pdf.txtSIQUEIRA, JUNARA VILLANOVA DE.pdf.txtExtracted texttext/plain136407http://repositorio.ufsm.br/bitstream/1/9252/2/SIQUEIRA%2c%20JUNARA%20VILLANOVA%20DE.pdf.txt4496d6d77f4f4964c5dd593adc14dab8MD52THUMBNAILSIQUEIRA, JUNARA VILLANOVA DE.pdf.jpgSIQUEIRA, JUNARA VILLANOVA DE.pdf.jpgIM Thumbnailimage/jpeg4641http://repositorio.ufsm.br/bitstream/1/9252/3/SIQUEIRA%2c%20JUNARA%20VILLANOVA%20DE.pdf.jpgaceffb00c164f086c171ea0bcd3314f0MD531/92522017-07-25 11:52:26.498oai:repositorio.ufsm.br:1/9252Repositório Institucionalhttp://repositorio.ufsm.br/PUBhttp://repositorio.ufsm.br/oai/requestopendoar:39132017-07-25T14:52:26Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false |
dc.title.por.fl_str_mv |
Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica |
dc.title.alternative.eng.fl_str_mv |
Exchange bias in NiFe/IrMn/Ta multilayers: a study through Anisotropic magnetoresistance |
title |
Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica |
spellingShingle |
Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica Siqueira, Junara Villanova de Magnetorresistência anisotrópica Exchange bias Anisotropia Ansotropic magnetoresistance Exchange bias Anisotropy CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica |
title_full |
Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica |
title_fullStr |
Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica |
title_full_unstemmed |
Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica |
title_sort |
Exchange bias em multicamadas de NiFe/IrMn/Ta: um estudo através da magnetorresistência anisotrópica |
author |
Siqueira, Junara Villanova de |
author_facet |
Siqueira, Junara Villanova de |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Carara, Marcos André |
dc.contributor.advisor1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4782774A7 |
dc.contributor.referee1.fl_str_mv |
Sossmeier, Kelly Daiane |
dc.contributor.referee1Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4771352J2 |
dc.contributor.referee2.fl_str_mv |
Calegari, Eleonir João |
dc.contributor.referee2Lattes.fl_str_mv |
http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4765559T0 |
dc.contributor.authorLattes.fl_str_mv |
http://lattes.cnpq.br/6247242479912175 |
dc.contributor.author.fl_str_mv |
Siqueira, Junara Villanova de |
contributor_str_mv |
Carara, Marcos André Sossmeier, Kelly Daiane Calegari, Eleonir João |
dc.subject.por.fl_str_mv |
Magnetorresistência anisotrópica Exchange bias Anisotropia |
topic |
Magnetorresistência anisotrópica Exchange bias Anisotropia Ansotropic magnetoresistance Exchange bias Anisotropy CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.eng.fl_str_mv |
Ansotropic magnetoresistance Exchange bias Anisotropy |
dc.subject.cnpq.fl_str_mv |
CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
description |
In this work a study of the exchange interaction between ferromagnetic (NiFe) and antiferromagnetic (IrMn) layers was done through structural, magnetic and electric characterization. NiFe/IrMn/Ta films were grown with different number of repetitions of this basic structure aiming to evaluate possible changes on the magnetic anisotropies presented by the samples. It was implanted in the Laboratório de Magnetismo e Materiais Magnéticos a system in order to measure the Anisotropic Magnetorresistance (AMR) as function of the applied field angle. The AMR consists in a change of the eletric resistance of a ferromagnetic material as function of the angle between the electric current and the magnetization of the material and, by this way, sensible to changes in the anisotropy presented by the samples. It is presented a simple model to calculate the AMR as function of the angle field and, by comparing with the experimental curves, to obtain the magnetic parameters who describe the system. In the model the equilibrium direction of the magnetization is obtained from the minimization of the free magnetic energy, which is given by the Zeeman, uniaxial, unidirectional and manetostatic energies. The AMR curves present an assymetry around 180 degrees when measured at fields below the bias one. According to the fittings, it was found that such assymetry can be due by a misalignment between the anisotropy axis (uniaxial and unidirectional) or by a misalignment between the measuring current and the easy magnetic axis of the samples. It was not observed, as expected, an expressive increase of the anisotropy dispersion of the uniaxial anisotropy with the increase of the number of trilayers. The same was observed with the bias and coercive fields. |
publishDate |
2015 |
dc.date.issued.fl_str_mv |
2015-08-07 |
dc.date.accessioned.fl_str_mv |
2017-05-09 |
dc.date.available.fl_str_mv |
2017-05-09 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.citation.fl_str_mv |
SIQUEIRA, Junara Villanova de. Exchange bias in NiFe/IrMn/Ta multilayers: a study through Anisotropic magnetoresistance. 2015. 81 f. Dissertação (Mestrado em Física) - Universidade Federal de Santa Maria, Santa Maria, 2015. |
dc.identifier.uri.fl_str_mv |
http://repositorio.ufsm.br/handle/1/9252 |
identifier_str_mv |
SIQUEIRA, Junara Villanova de. Exchange bias in NiFe/IrMn/Ta multilayers: a study through Anisotropic magnetoresistance. 2015. 81 f. Dissertação (Mestrado em Física) - Universidade Federal de Santa Maria, Santa Maria, 2015. |
url |
http://repositorio.ufsm.br/handle/1/9252 |
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por |
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Universidade Federal de Santa Maria |
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UFSM |
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BR |
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Física |
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Universidade Federal de Santa Maria |
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