Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa
Autor(a) principal: | |
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Data de Publicação: | 2016 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Manancial - Repositório Digital da UFSM |
Texto Completo: | http://repositorio.ufsm.br/handle/1/12406 |
Resumo: | Magnetic materials when reduced to the nanoscale promote the emergence of new properties and the specific functionalization of these magnetic nanostructures are key tools in the development of improved devices for information technology (memory and data processing) and detection. In this thesis were electro-deposited magnetic nanotubes in anodic aluminum membranes. The properties of magnetic nanotube networks of Ni, Co, FeCo and FeNi with different geometric parameters were investigated. The porous aluminum oxide membranes were prepared using the hard anodizing process, in a self-ordering regime with pore distances Dint=300nm. This process offers substantial advantages over conventional anodizing processes in terms of processing time, allowing for faster oxide growth, with better arrangement and high aspect ratio of nanopores. The nanotubes were electrodeposited through the potentiostat mode, using porous membranes as the basis for their structure. Samples with external diameter of 140nm, 180nm and 220nm were obtained. In addition, the nanotubes have an additional degree of freedom given by the thickness of the tube walls. In this way, nanotubes with constant external diameter and different wall thicknesses of the tube were also synthesized. The structure and morphologies of the synthesized samples were characterized by scanning electron microscopy, x-ray dispersion spectroscopy and x-ray diffraction. The magnetic characterization was performed through the vibrating sample magnetometer. Through the nanotubes with different diameters it was possible to observe that the global anisotropy of the matrix is the result of the competition between the magnetostatic interactions, magnetocrystalline anisotropy and form anisotropy. With the increase of the diameter of NTs and the decrease of the distance between them it was observed that the magnetostatic interactions prevail. Nanotubes with different wall thicknesses were produced, maintaining constant the external diameter and the distance between the structures. Through the characterization of these structures it was observed that for nearby nanotubes, with distances smaller than their diameter, it is the wall thickness that determines the magnetic interaction between the nanotubes of the network. The magnetization inversion processes for NTs with different wall thicknesses were investigated through the analysis of the coercive field as a function of the applied field. It can be seen that the same structure can present two types of magnetization inversion, the transverse mode or vortex, and that this inversion can be determined by adjusting the NT wall thickness. The comparative study between the nanotubes with different compositions and geometric parameters showed that the magnetic properties are strongly correlated with the geometric parameters. |
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Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosaNanomagnetismoNanotubos magnéticosEletrodeposição em AAOMembrana anódicaNanomagnetismMagnetic nanotubesElectrodepositionAnodic membraneCNPQ::CIENCIAS EXATAS E DA TERRA::FISICAMagnetic materials when reduced to the nanoscale promote the emergence of new properties and the specific functionalization of these magnetic nanostructures are key tools in the development of improved devices for information technology (memory and data processing) and detection. In this thesis were electro-deposited magnetic nanotubes in anodic aluminum membranes. The properties of magnetic nanotube networks of Ni, Co, FeCo and FeNi with different geometric parameters were investigated. The porous aluminum oxide membranes were prepared using the hard anodizing process, in a self-ordering regime with pore distances Dint=300nm. This process offers substantial advantages over conventional anodizing processes in terms of processing time, allowing for faster oxide growth, with better arrangement and high aspect ratio of nanopores. The nanotubes were electrodeposited through the potentiostat mode, using porous membranes as the basis for their structure. Samples with external diameter of 140nm, 180nm and 220nm were obtained. In addition, the nanotubes have an additional degree of freedom given by the thickness of the tube walls. In this way, nanotubes with constant external diameter and different wall thicknesses of the tube were also synthesized. The structure and morphologies of the synthesized samples were characterized by scanning electron microscopy, x-ray dispersion spectroscopy and x-ray diffraction. The magnetic characterization was performed through the vibrating sample magnetometer. Through the nanotubes with different diameters it was possible to observe that the global anisotropy of the matrix is the result of the competition between the magnetostatic interactions, magnetocrystalline anisotropy and form anisotropy. With the increase of the diameter of NTs and the decrease of the distance between them it was observed that the magnetostatic interactions prevail. Nanotubes with different wall thicknesses were produced, maintaining constant the external diameter and the distance between the structures. Through the characterization of these structures it was observed that for nearby nanotubes, with distances smaller than their diameter, it is the wall thickness that determines the magnetic interaction between the nanotubes of the network. The magnetization inversion processes for NTs with different wall thicknesses were investigated through the analysis of the coercive field as a function of the applied field. It can be seen that the same structure can present two types of magnetization inversion, the transverse mode or vortex, and that this inversion can be determined by adjusting the NT wall thickness. The comparative study between the nanotubes with different compositions and geometric parameters showed that the magnetic properties are strongly correlated with the geometric parameters.Materiais magnéticos quando reduzidos à escala nanométrica promovem o surgimento de novas propriedades e a funcionalização específica dessas nanoestruturas magnéticas são ferramentas chave no desenvolvimento de dispositivos aprimorados para tecnologia da informação (memória e processamento de dados) e detecção. Nesta tese foram sintetizados nanotubos magnéticos eletrodespositados em membranas de alumínio anódico. Foram investigadas as propriedades de redes de nanotubos magnéticos de Ni, Co, FeCo e FeNi, com diferentes parâmetros geométricos. As membranas de óxido de alumínio poroso foram preparadas utilizando o processo de anodização dura, em um regime de auto-ordenação com distâncias entre poros Dint=300nm. Este processo oferece vantagens substanciais em relação aos processos convencionais de anodização em termos do tempo de processamento, permitindo um crescimento mais rápido de óxido, com um melhor ordenamento e alta razão de aspecto dos nanoporos. Os nanotubos foram eletrodepositados através do modo potenciostato, utilizando as membranas porosas como base para sua estrutura. Foram obtidas amostras com diâmetro externo de 140nm, 180nm e 220nm. Além disso, os nanotubos apresentam um grau de liberdade adicional dado pela espessura das paredes do tubo. Dessa forma, também foram sintetizados nanotubos com diâmetro externo constante e com diferentes espessuras de parede do tubo. As estrutura e morfologias das amostras sintetizadas foram caracterizadas por microscopia eletrônica de varredura, espectroscopia de dispersão de raio-x e difratometria de raio-x. A caracterização magnética foi realizada através do magnetômetro de amostra vibrante. Através dos nanotubos com diferentes diâmetros foi possível observar que a anisotropia global da matriz é o resultado da competição entre as interações magnetostáticas, anisotropia magnetocristalina e anisotropia de forma. Com o aumento do diâmetro dos NTs e a diminuição da distância entre eles foi observado que as interações magnetostáticas prevalecem. Nanotubos com diferentes espessuras de parede foram produzidos, mantendo constante o diâmetro externo e a distância estre as estruturas. Através da caracterização dessas estruturas foi observado que para nanotubos próximos, com distâncias menores que seu diâmetro, é a espessura da parede que determina a interação magnética entre os nanotubos da rede. Os processos de inversão de magnetização para NTs com diferentes espessuras de parede foi investigado através da análise do campo coercivo em função do campo aplicado. Mostrando que a mesma estrutura pode apresentar dois tipos de inversão de magnetização, o modo transversal ou vórtice, e que esta inversão pode ser determinada através do ajusta da espessura de parede do NT. O estudo comparativo entre os nanotubos com diferentes composições e parâmetros geométricos mostrou que as propriedades magnéticas são fortemente correlacionadas com os parâmetros geométricos.Universidade Federal de Santa MariaBrasilFísicaUFSMPrograma de Pós-Graduação em FísicaCentro de Ciências Naturais e ExatasDorneles, Lucio Strazzaboscohttp://lattes.cnpq.br/7244173039310066Viegas, Alexandre Da Cashttp://lattes.cnpq.br/5936503285330202Gündel, Andréhttp://lattes.cnpq.br/9063998902105812Oliveira, Artur Harres dehttp://lattes.cnpq.br/5413344891000141Calegari, Eleonir Joãohttp://lattes.cnpq.br/6030572534512173Chrischon, Dieivase da Silva2018-02-14T11:29:38Z2018-02-14T11:29:38Z2016-09-09info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisapplication/pdfhttp://repositorio.ufsm.br/handle/1/12406porAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/openAccessreponame:Manancial - Repositório Digital da UFSMinstname:Universidade Federal de Santa Maria (UFSM)instacron:UFSM2022-01-06T12:24:40Zoai:repositorio.ufsm.br:1/12406Biblioteca Digital de Teses e Dissertaçõeshttps://repositorio.ufsm.br/ONGhttps://repositorio.ufsm.br/oai/requestatendimento.sib@ufsm.br||tedebc@gmail.comopendoar:2022-01-06T12:24:40Manancial - Repositório Digital da UFSM - Universidade Federal de Santa Maria (UFSM)false |
dc.title.none.fl_str_mv |
Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa |
title |
Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa |
spellingShingle |
Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa Chrischon, Dieivase da Silva Nanomagnetismo Nanotubos magnéticos Eletrodeposição em AAO Membrana anódica Nanomagnetism Magnetic nanotubes Electrodeposition Anodic membrane CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa |
title_full |
Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa |
title_fullStr |
Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa |
title_full_unstemmed |
Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa |
title_sort |
Nanotubos magnéticos sintetizados por eletrodeposição em alumina anódica porosa |
author |
Chrischon, Dieivase da Silva |
author_facet |
Chrischon, Dieivase da Silva |
author_role |
author |
dc.contributor.none.fl_str_mv |
Dorneles, Lucio Strazzabosco http://lattes.cnpq.br/7244173039310066 Viegas, Alexandre Da Cas http://lattes.cnpq.br/5936503285330202 Gündel, André http://lattes.cnpq.br/9063998902105812 Oliveira, Artur Harres de http://lattes.cnpq.br/5413344891000141 Calegari, Eleonir João http://lattes.cnpq.br/6030572534512173 |
dc.contributor.author.fl_str_mv |
Chrischon, Dieivase da Silva |
dc.subject.por.fl_str_mv |
Nanomagnetismo Nanotubos magnéticos Eletrodeposição em AAO Membrana anódica Nanomagnetism Magnetic nanotubes Electrodeposition Anodic membrane CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
topic |
Nanomagnetismo Nanotubos magnéticos Eletrodeposição em AAO Membrana anódica Nanomagnetism Magnetic nanotubes Electrodeposition Anodic membrane CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA |
description |
Magnetic materials when reduced to the nanoscale promote the emergence of new properties and the specific functionalization of these magnetic nanostructures are key tools in the development of improved devices for information technology (memory and data processing) and detection. In this thesis were electro-deposited magnetic nanotubes in anodic aluminum membranes. The properties of magnetic nanotube networks of Ni, Co, FeCo and FeNi with different geometric parameters were investigated. The porous aluminum oxide membranes were prepared using the hard anodizing process, in a self-ordering regime with pore distances Dint=300nm. This process offers substantial advantages over conventional anodizing processes in terms of processing time, allowing for faster oxide growth, with better arrangement and high aspect ratio of nanopores. The nanotubes were electrodeposited through the potentiostat mode, using porous membranes as the basis for their structure. Samples with external diameter of 140nm, 180nm and 220nm were obtained. In addition, the nanotubes have an additional degree of freedom given by the thickness of the tube walls. In this way, nanotubes with constant external diameter and different wall thicknesses of the tube were also synthesized. The structure and morphologies of the synthesized samples were characterized by scanning electron microscopy, x-ray dispersion spectroscopy and x-ray diffraction. The magnetic characterization was performed through the vibrating sample magnetometer. Through the nanotubes with different diameters it was possible to observe that the global anisotropy of the matrix is the result of the competition between the magnetostatic interactions, magnetocrystalline anisotropy and form anisotropy. With the increase of the diameter of NTs and the decrease of the distance between them it was observed that the magnetostatic interactions prevail. Nanotubes with different wall thicknesses were produced, maintaining constant the external diameter and the distance between the structures. Through the characterization of these structures it was observed that for nearby nanotubes, with distances smaller than their diameter, it is the wall thickness that determines the magnetic interaction between the nanotubes of the network. The magnetization inversion processes for NTs with different wall thicknesses were investigated through the analysis of the coercive field as a function of the applied field. It can be seen that the same structure can present two types of magnetization inversion, the transverse mode or vortex, and that this inversion can be determined by adjusting the NT wall thickness. The comparative study between the nanotubes with different compositions and geometric parameters showed that the magnetic properties are strongly correlated with the geometric parameters. |
publishDate |
2016 |
dc.date.none.fl_str_mv |
2016-09-09 2018-02-14T11:29:38Z 2018-02-14T11:29:38Z |
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 |
http://repositorio.ufsm.br/handle/1/12406 |
url |
http://repositorio.ufsm.br/handle/1/12406 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.rights.driver.fl_str_mv |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
application/pdf |
dc.publisher.none.fl_str_mv |
Universidade Federal de Santa Maria Brasil Física UFSM Programa de Pós-Graduação em Física Centro de Ciências Naturais e Exatas |
publisher.none.fl_str_mv |
Universidade Federal de Santa Maria Brasil Física UFSM Programa de Pós-Graduação em Física Centro de Ciências Naturais e Exatas |
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 |
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1805922161851891712 |