Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3
Autor(a) principal: | |
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Data de Publicação: | 2022 |
Tipo de documento: | Tese |
Idioma: | por |
Título da fonte: | Repositório Institucional da UFS |
Texto Completo: | http://ri.ufs.br/jspui/handle/riufs/16851 |
Resumo: | In this work the structural and magnetic properties of the orthochomites Nd1-xPrxCrO3 (0 ≤ x ≤ 1) and Nd1-xDyxCrO3 (x = 0.05 and 0.20) compounds obtained by co-precipitation method were studied. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), magnetization measurements as a function of the temperature (MvsT) and magnetic field (MvsH). The samples Nd1-xPrxCrO3 exihibit a single phase with orthorhombic symmetry, Pnma space group and slight changes in the structural parameters as a function of the Pr3+ concentration. EDS results confirm the incorporation of Pr3+ ions into structure consistent with nominal concentration of the samples. MvsT curves show a gradual increase in the antiferromagnetic phase transition temperature of the Cr sublattice as a function of increasing Pr3+ concentration. Furthermore, spin reorientation temperature (TRS ≈ 35 K) of the sample x = 0 is suppressed with the addition of the Pr3+ dopant. Below Néel temperature, compensation temperature and magnetization reversal are observed for samples between 0.15 ≤ x ≤ 0.60, suggesting that the non-Kramer Pr3+ ion may play an important role in the magnetic properties of the system. MvsH measurements show the presence of a antiferromagnetic state accompanied by a weak ferromagnetic contribution and conventional (ZFC) and spontaneous (FC) exchange bias (EB) effects. The sign of the exchange bias field (negative and positive) and magnetization reversal can be tunning by the Pr3+ concentration, temperature and cooling magnetic field, indicating a strong correlation between them. Both EB and MR show a dependence on the absolute value of the total magnetization of the rare earth ion sublattice. In addition, the particle-size effects on the magnetic properties were investigated in the Nd0.5Pr0.5CrO3 and Nd1-xDyxCrO3 samples calcined at different temperatures. XRD data and SEM images show clearly in both cases an increase in particle sizes as a function of the calcination temperature. Furthermore, no significant changes were observed in Néel temperatures with increasing calcination temperature. In particular case of the Nd0.5Pr0.5CrO3 sample, it is observed a increase in the compensation temperature with increasing particle size. The MvsH curves indicate the presence of the phenomenon of positive and negative EB for the samples doped with Pr and Dy, respectively. Exchange bias field values increase with particle size reduction. This behavior may be associated to a variation in the fraction of ferromagnetic clusters on the surface of the particles and in the antiferromagnetic spins into core. |
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Barbosa, Cristiane Cupertino SantosMeneses, Cristiano Teles de2022-11-30T12:32:11Z2022-11-30T12:32:11Z2022-08-23BARBOSA, Cristiane Cupertino Santos. Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3. 2022. 131 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2022.http://ri.ufs.br/jspui/handle/riufs/16851In this work the structural and magnetic properties of the orthochomites Nd1-xPrxCrO3 (0 ≤ x ≤ 1) and Nd1-xDyxCrO3 (x = 0.05 and 0.20) compounds obtained by co-precipitation method were studied. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), magnetization measurements as a function of the temperature (MvsT) and magnetic field (MvsH). The samples Nd1-xPrxCrO3 exihibit a single phase with orthorhombic symmetry, Pnma space group and slight changes in the structural parameters as a function of the Pr3+ concentration. EDS results confirm the incorporation of Pr3+ ions into structure consistent with nominal concentration of the samples. MvsT curves show a gradual increase in the antiferromagnetic phase transition temperature of the Cr sublattice as a function of increasing Pr3+ concentration. Furthermore, spin reorientation temperature (TRS ≈ 35 K) of the sample x = 0 is suppressed with the addition of the Pr3+ dopant. Below Néel temperature, compensation temperature and magnetization reversal are observed for samples between 0.15 ≤ x ≤ 0.60, suggesting that the non-Kramer Pr3+ ion may play an important role in the magnetic properties of the system. MvsH measurements show the presence of a antiferromagnetic state accompanied by a weak ferromagnetic contribution and conventional (ZFC) and spontaneous (FC) exchange bias (EB) effects. The sign of the exchange bias field (negative and positive) and magnetization reversal can be tunning by the Pr3+ concentration, temperature and cooling magnetic field, indicating a strong correlation between them. Both EB and MR show a dependence on the absolute value of the total magnetization of the rare earth ion sublattice. In addition, the particle-size effects on the magnetic properties were investigated in the Nd0.5Pr0.5CrO3 and Nd1-xDyxCrO3 samples calcined at different temperatures. XRD data and SEM images show clearly in both cases an increase in particle sizes as a function of the calcination temperature. Furthermore, no significant changes were observed in Néel temperatures with increasing calcination temperature. In particular case of the Nd0.5Pr0.5CrO3 sample, it is observed a increase in the compensation temperature with increasing particle size. The MvsH curves indicate the presence of the phenomenon of positive and negative EB for the samples doped with Pr and Dy, respectively. Exchange bias field values increase with particle size reduction. This behavior may be associated to a variation in the fraction of ferromagnetic clusters on the surface of the particles and in the antiferromagnetic spins into core.Neste trabalho foram estudadas as propriedades estruturais e magnéticas dos compostos ortocromitas Nd1-xPrxCrO3 (0 ≤ x ≤ 1) e Nd1-xDyxCrO3 (x = 0,05 e 0,20) obtidos pelo método de co-precipitação. As amostras foram caracterizadas por meio de medidas de difração de raios X (DRX), microscopia eletrônica de varredura (MEV), espectroscopia por energia dispersiva de raios X (EDS), medidas de magnetização em função da temperatura (MvsT) e do campo magnético (MvsH). As amostras do sistema Nd1-xPrxCrO3 apresentam uma única fase cristalina com simetria ortorrômbica, grupo espacial Pnma e leves alterações nos parâmetros estruturais em função da concentração de Pr3+ . Análises de EDS confirmam a incorporação dos íons Pr3+ na estrutura consistente com a concentração nominal das amostras. As curvas de MvsT mostram um aumento gradativo da temperatura de transição antiferromagnética (TN) da sub-rede do Cr3+ com o aumento da concentração do Pr3+ . Além disso, a temperatura de reorientação de spin (TRS ≈ 35 K) da amostra x = 0 é suprimida com a adição do Pr3+ . Abaixo da TN observa-se a presença de temperatura de compensação e magnetização reversa (MR) para amostras entre 0,15 ≤ x ≤ 0,60, sugerindo que a dopagem com o íon não Kramer Pr3+ pode desempenhar um papel importante nas propriedades magnéticas do sistema. Medidas de MvsH mostram a presença de um estado antiferromagnético acompanhado de uma contribuição ferromagnética fraca e efeitos de exchange bias (EB) convencional (FC) e espontâneo (ZFC). O sinal do campo de EB (HEB) (negativo ou positivo) e a MR podem ser sintonizados variando a concentração de Pr3+ , indicando uma forte correlação entre os efeitos. Tanto o EB quanto a MR mostram uma dependência com o valor absoluto da magnetização total da sub-rede do íon terra rara. Além disso, ambos os fenômenos exibem uma forte dependência com a temperatura e com o campo magnético de resfriamento. Adicionalmente, foram investigados os efeitos do tamanho das partículas nas propriedades magnéticas das amostras Nd0,5Pr0,5CrO3 e Nd1-xDyxCrO3 calcinadas em diferentes temperaturas. Nesses casos, os dados de DRX e as imagens MEV mostram claramente um aumento do tamanho da partícula em função da temperatura de calcinação. Além disso, não foram observadas mudanças significativas da TN com o aumento da temperatura de calcinação. Observa-se, particularmente para a amostra Nd0,5Pr0,5CrO3, um aumento da temperatura de compensação com o aumento do tamanho da partícula. As curvas de MvsH indicam a presença do fenômeno de EB positivo e negativo para as amostras dopadas com Pr3+ e Dy3+, respectivamente. A intensidade do HEB aumenta com a redução do tamanho das ix partículas. Este comportamento pode estar relacionado a uma variação na fração de clusters ferromagnéticos na superfície da partícula e dos spins antiferromagnéticos do núcleo.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESSão CristóvãoporOrtocromitasMagnetização reversaExchange biasOrthochromitesMagnetization reversalExchange BiasCIENCIAS EXATAS E DA TERRA::FISICAEstudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisPós-Graduação em FísicaUniversidade Federal de Sergipereponame:Repositório Institucional da UFSinstname:Universidade Federal de Sergipe (UFS)instacron:UFSinfo:eu-repo/semantics/openAccessLICENSElicense.txtlicense.txttext/plain; charset=utf-81475https://ri.ufs.br/jspui/bitstream/riufs/16851/1/license.txt098cbbf65c2c15e1fb2e49c5d306a44cMD51ORIGINALCRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdfCRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdfapplication/pdf6421694https://ri.ufs.br/jspui/bitstream/riufs/16851/2/CRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdf7ba6e9fb302c041bb061d4ef2f531351MD52TEXTCRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdf.txtCRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdf.txtExtracted texttext/plain274375https://ri.ufs.br/jspui/bitstream/riufs/16851/3/CRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdf.txt07d2a01cf68af120008b17e178aa3526MD53THUMBNAILCRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdf.jpgCRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdf.jpgGenerated Thumbnailimage/jpeg1262https://ri.ufs.br/jspui/bitstream/riufs/16851/4/CRISTIANE_CUPERTINO_SANTOS_BARBOSA.pdf.jpg3f98e7b71f28da52228cc2ea39324e61MD54riufs/168512022-11-30 09:32:12.051oai:ufs.br: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Repositório InstitucionalPUBhttps://ri.ufs.br/oai/requestrepositorio@academico.ufs.bropendoar:2022-11-30T12:32:12Repositório Institucional da UFS - Universidade Federal de Sergipe (UFS)false |
dc.title.pt_BR.fl_str_mv |
Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3 |
title |
Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3 |
spellingShingle |
Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3 Barbosa, Cristiane Cupertino Santos Ortocromitas Magnetização reversa Exchange bias Orthochromites Magnetization reversal Exchange Bias CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3 |
title_full |
Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3 |
title_fullStr |
Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3 |
title_full_unstemmed |
Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3 |
title_sort |
Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3 |
author |
Barbosa, Cristiane Cupertino Santos |
author_facet |
Barbosa, Cristiane Cupertino Santos |
author_role |
author |
dc.contributor.author.fl_str_mv |
Barbosa, Cristiane Cupertino Santos |
dc.contributor.advisor1.fl_str_mv |
Meneses, Cristiano Teles de |
contributor_str_mv |
Meneses, Cristiano Teles de |
dc.subject.por.fl_str_mv |
Ortocromitas Magnetização reversa Exchange bias |
topic |
Ortocromitas Magnetização reversa Exchange bias Orthochromites Magnetization reversal Exchange Bias CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.eng.fl_str_mv |
Orthochromites Magnetization reversal Exchange Bias |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::FISICA |
description |
In this work the structural and magnetic properties of the orthochomites Nd1-xPrxCrO3 (0 ≤ x ≤ 1) and Nd1-xDyxCrO3 (x = 0.05 and 0.20) compounds obtained by co-precipitation method were studied. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), magnetization measurements as a function of the temperature (MvsT) and magnetic field (MvsH). The samples Nd1-xPrxCrO3 exihibit a single phase with orthorhombic symmetry, Pnma space group and slight changes in the structural parameters as a function of the Pr3+ concentration. EDS results confirm the incorporation of Pr3+ ions into structure consistent with nominal concentration of the samples. MvsT curves show a gradual increase in the antiferromagnetic phase transition temperature of the Cr sublattice as a function of increasing Pr3+ concentration. Furthermore, spin reorientation temperature (TRS ≈ 35 K) of the sample x = 0 is suppressed with the addition of the Pr3+ dopant. Below Néel temperature, compensation temperature and magnetization reversal are observed for samples between 0.15 ≤ x ≤ 0.60, suggesting that the non-Kramer Pr3+ ion may play an important role in the magnetic properties of the system. MvsH measurements show the presence of a antiferromagnetic state accompanied by a weak ferromagnetic contribution and conventional (ZFC) and spontaneous (FC) exchange bias (EB) effects. The sign of the exchange bias field (negative and positive) and magnetization reversal can be tunning by the Pr3+ concentration, temperature and cooling magnetic field, indicating a strong correlation between them. Both EB and MR show a dependence on the absolute value of the total magnetization of the rare earth ion sublattice. In addition, the particle-size effects on the magnetic properties were investigated in the Nd0.5Pr0.5CrO3 and Nd1-xDyxCrO3 samples calcined at different temperatures. XRD data and SEM images show clearly in both cases an increase in particle sizes as a function of the calcination temperature. Furthermore, no significant changes were observed in Néel temperatures with increasing calcination temperature. In particular case of the Nd0.5Pr0.5CrO3 sample, it is observed a increase in the compensation temperature with increasing particle size. The MvsH curves indicate the presence of the phenomenon of positive and negative EB for the samples doped with Pr and Dy, respectively. Exchange bias field values increase with particle size reduction. This behavior may be associated to a variation in the fraction of ferromagnetic clusters on the surface of the particles and in the antiferromagnetic spins into core. |
publishDate |
2022 |
dc.date.accessioned.fl_str_mv |
2022-11-30T12:32:11Z |
dc.date.available.fl_str_mv |
2022-11-30T12:32:11Z |
dc.date.issued.fl_str_mv |
2022-08-23 |
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 |
BARBOSA, Cristiane Cupertino Santos. Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3. 2022. 131 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2022. |
dc.identifier.uri.fl_str_mv |
http://ri.ufs.br/jspui/handle/riufs/16851 |
identifier_str_mv |
BARBOSA, Cristiane Cupertino Santos. Estudo da correlação do efeito de exchange bias com a magnetização reversa em ortocromitas do tipo Nd1-x(Pr,Dy)xCrO3. 2022. 131 f. Tese (Doutorado em Física) - Universidade Federal de Sergipe, São Cristóvão, 2022. |
url |
http://ri.ufs.br/jspui/handle/riufs/16851 |
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por |
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por |
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info:eu-repo/semantics/openAccess |
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openAccess |
dc.publisher.program.fl_str_mv |
Pós-Graduação em Física |
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Universidade Federal de Sergipe |
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