Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.

Detalhes bibliográficos
Autor(a) principal: Paris, Elaine Cristina
Data de Publicação: 2005
Tipo de documento: Tese
Idioma: por
Título da fonte: Repositório Institucional da UFSCAR
Texto Completo: https://repositorio.ufscar.br/handle/ufscar/6353
Resumo: In this work, it was obtained powders and thin films of (Pb1-xLnx)TiO3, Ln = Sm and Er, using a chemical method of synthesis, polymeric precursor method (Pechini). In this way, the synthesis conditions were optimized in order to minimize the formation of secondary phases. (Pb1-xSmx)TiO3, PST and (Pb1-xErx)TiO3, PET powders, with x varying from 0.01 to 0.1, were obtained in pH 7 and calcined at 600°C for 2 and 8 hours in oxygen atmosphere. There was not formation of secondary phase (pyrochlore) up to 4 mol% of Sm. On the other hand, the solubility limit was already reached at the PbTiO3 (PT) lattice, when doped with 4 mol% of Er. The increase of the percentage of dopants favors the beginning of the tetragonal to cubic phase transition. In this transition, up to 2 mol% of dopants, Er is more efficient than Sm and for above that, an inversion of this behavior occurs. It was observed by micro-Raman spectroscopy and DSC that the addition of Sm or Er to the PT causes a decrease of Curie temperature of the material in relation to the pure PT (~ 490°C). PST and PET thin films were obtained by spin coating on Pt/Ti/SiO2/Si substrate and heat treated at 600°C for 2 hours for the crystallization of the films. It was observed for both PST and PET films are occurring the beginning of the tetragonal to cubic phase transition, resulting in PT with low tetragonality, with the increase of the dopants concentration. It was also verified that these films are textured in the (001) and (100) family plans with both dopants, being a axis direction favored. The obtained films presented nanometric grain sizes and the addition of dopants (Sm or Er) in the PT lattice resulted in a decrease of the average grain size. In order to improving the dielectric and ferroelectric properties of the PST and PET films, it was varied: Sm or Er concentration, number of layers, viscosity of the precursor solution, deposition speed, heat treatment, the bottom electrode and the organic precursor concentration. In the results of electric measurements, it was verified that the Er addition is more efficient than Sm in the increase of the dielectric constant and improvement of ferroelectric properties of the films. It was also observed that the decrease of the tetragonality of the films, with the consequent beginning of the tetragonal to cubic phase transition of the material, there is a reduction of the dielectric constant values and of the remanent polarization for the samples. Using the LaNiO3 like bottom electrode in substitution to the Pt, it was obtained approximated values of dielectric constant, however this substitution resulted in better ferroelectric properties of the films. In spite of obtaining smaller dielectric constant values than those found in the literature, it could be observed that the decrease of the concentration of organic precursors improved the electric properties of the PST and PET films, indicating a dependence relationship of the amount of organic material present in the precursor solution in function of obtaining thin films with satisfactory dielectric and ferroelectric properties.
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spelling Paris, Elaine CristinaLeite, Edson Robertohttp://genos.cnpq.br:12010/dwlattes/owa/prc_imp_cv_int?f_cod=K4783657E4http://genos.cnpq.br:12010/dwlattes/owa/prc_imp_cv_int?f_cod=K4700940J82b06dcbe-d595-48de-ad9e-26077464fa042016-06-02T20:35:05Z2007-07-102016-06-02T20:35:05Z2005-04-29PARIS, Elaine Cristina. Study of influence of Sm and Er on PbTiO3 ceramics.. 2005. 238 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2005.https://repositorio.ufscar.br/handle/ufscar/6353In this work, it was obtained powders and thin films of (Pb1-xLnx)TiO3, Ln = Sm and Er, using a chemical method of synthesis, polymeric precursor method (Pechini). In this way, the synthesis conditions were optimized in order to minimize the formation of secondary phases. (Pb1-xSmx)TiO3, PST and (Pb1-xErx)TiO3, PET powders, with x varying from 0.01 to 0.1, were obtained in pH 7 and calcined at 600°C for 2 and 8 hours in oxygen atmosphere. There was not formation of secondary phase (pyrochlore) up to 4 mol% of Sm. On the other hand, the solubility limit was already reached at the PbTiO3 (PT) lattice, when doped with 4 mol% of Er. The increase of the percentage of dopants favors the beginning of the tetragonal to cubic phase transition. In this transition, up to 2 mol% of dopants, Er is more efficient than Sm and for above that, an inversion of this behavior occurs. It was observed by micro-Raman spectroscopy and DSC that the addition of Sm or Er to the PT causes a decrease of Curie temperature of the material in relation to the pure PT (~ 490°C). PST and PET thin films were obtained by spin coating on Pt/Ti/SiO2/Si substrate and heat treated at 600°C for 2 hours for the crystallization of the films. It was observed for both PST and PET films are occurring the beginning of the tetragonal to cubic phase transition, resulting in PT with low tetragonality, with the increase of the dopants concentration. It was also verified that these films are textured in the (001) and (100) family plans with both dopants, being a axis direction favored. The obtained films presented nanometric grain sizes and the addition of dopants (Sm or Er) in the PT lattice resulted in a decrease of the average grain size. In order to improving the dielectric and ferroelectric properties of the PST and PET films, it was varied: Sm or Er concentration, number of layers, viscosity of the precursor solution, deposition speed, heat treatment, the bottom electrode and the organic precursor concentration. In the results of electric measurements, it was verified that the Er addition is more efficient than Sm in the increase of the dielectric constant and improvement of ferroelectric properties of the films. It was also observed that the decrease of the tetragonality of the films, with the consequent beginning of the tetragonal to cubic phase transition of the material, there is a reduction of the dielectric constant values and of the remanent polarization for the samples. Using the LaNiO3 like bottom electrode in substitution to the Pt, it was obtained approximated values of dielectric constant, however this substitution resulted in better ferroelectric properties of the films. In spite of obtaining smaller dielectric constant values than those found in the literature, it could be observed that the decrease of the concentration of organic precursors improved the electric properties of the PST and PET films, indicating a dependence relationship of the amount of organic material present in the precursor solution in function of obtaining thin films with satisfactory dielectric and ferroelectric properties.Neste trabalho, realizou-se a obtenção de pós e filmes finos de (Pb1-xLnx)TiO3, com Ln = Sm e Er, utilizando-se um método de síntese química, o método dos precursores poliméricos (método Pechini). Para isto, otimizou-se as condições de síntese de modo a minimizar a presença de fases secundárias. Obteve-se pós de (Pb1- xSmx)TiO3, PST e (Pb1-xErx)TiO3, PET, com x variando de 0,01 a 0,1, em pH 7 e verificou-se, para estes pós calcinados a 600°C por 2 e 8 horas em fluxo de oxigênio, que não houve a presença de fase secundária (pirocloro) até 4% em molde Sm, sendo que para o Er nesta adição, já é atingido o limite de solubilidade na matriz do PbTiO3 (PT). Verificou-se também, por difração de raios X (DRX) e espectroscopia Raman que o aumento da porcentagem dos aditivos, favorece o início da transição de fase tetragonal para cúbica do PT, sendo que até 2% em mol do aditivo, o Er é mais eficiente que o Sm neste processo e que para as adições superiores, há uma inversão de comportamento. Verificou-se por micro-Raman e por calorimetria exploratória diferencial (DSC), que a adição de Sm ou Er ao PT causa uma diminuição da temperatura de Curie do material em relação ao PT puro que é de 490°C. Foram obtidos filmes finos de PST e PET, depositados por spin coating sobre substratos de Pt/Ti/SiO2/Si e tratados termicamente a 600°C por 2 horas para a cristalização. De maneira análoga aos pós, observou-se tanto para os filmes de PST como para os de PET, que está havendo o início da transição de fase tetragonal para cúbica, resultando em PT com baixa tetragonalidade, com o aumento da concentração de dopantes. Verificou-se também, que houve texturização dos filmes nas famílias de planos (001) e (100), para ambos os dopantes. Sendo que, a texturização na direção do eixo a é mais favorecida. Pôdese verificar por microscopia de força atômica, que foram obtidos filmes com tamanhos de grão nanométricos e que a introdução do dopante (Sm ou Er) na matriz do PT resulta em uma diminuição do tamanho médio de grãos dos filmes obtidos. No intuito de melhorar as propriedades dielétricas e ferrelétricas dos filmes de PST e PET, foram variadas: a concentração de Sm ou Er, o número de camadas dos filmes, a viscosidade da solução, a elocidade de deposição, o tratamento térmico, o eletrodo de base e a concentração de precursores orgânicos. Nos resultados de medidas elétricas, verificou-se que a adição de Er é mais eficiente que a de Sm no aumento da constante dielétrica e na melhora das propriedades ferrelétricas dos filmes. Observou-se também, que a diminuição da tetragonalidade dos filmes, com o conseqüente início da transição de fase tetragonal para cúbica do material, diminui os valores de constante dielétrica e de polarização remanescente para os mesmos. Verificou-se que a utilização do eletrodo base de LaNiO3 em substituição ao de Pt forneceu valores próximos de constante dielétrica, porém resultou em melhores propriedades ferrelétricas dos filmes. Apesar de terem sido obtidos valores de constante dielétrica inferiores aos da literatura, pôde-se observar que a diminuição da concentração de precursores orgânicos melhorou as propriedades elétricas dos filmes de PST e PET obtidos, indicando uma relação de dependência da quantidade de matéria orgânica presente na solução precursora, com a obtenção de filmes finos com propriedades dielétricas e ferrelétricas satisfatórias.Universidade Federal de Minas Geraisapplication/pdfporUniversidade Federal de São CarlosPrograma de Pós-Graduação em Química - PPGQUFSCarBRFísico-químicaTitanato de chumboTerras rarasMétodo dos precursores polimétricosFilmes finosCIENCIAS EXATAS E DA TERRA::QUIMICAEstudo da Influência do Sm e Er em Cerâmicas de PbTiO3.Study of influence of Sm and Er on PbTiO3 ceramics.info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesis-1-19c25e6a7-a2cd-4058-97ed-441bc2793123info:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFSCARinstname:Universidade Federal de São Carlos (UFSCAR)instacron:UFSCARORIGINALTeseECP.pdfapplication/pdf21825707https://repositorio.ufscar.br/bitstream/ufscar/6353/1/TeseECP.pdfb24b38448dae2c7b1da494a26fb8b0feMD51THUMBNAILTeseECP.pdf.jpgTeseECP.pdf.jpgIM Thumbnailimage/jpeg7922https://repositorio.ufscar.br/bitstream/ufscar/6353/2/TeseECP.pdf.jpgd5266703f22ae0b920eca9baff950fc8MD52ufscar/63532023-09-18 18:31:11.149oai:repositorio.ufscar.br:ufscar/6353Repositório InstitucionalPUBhttps://repositorio.ufscar.br/oai/requestopendoar:43222023-09-18T18:31:11Repositório Institucional da UFSCAR - Universidade Federal de São Carlos (UFSCAR)false
dc.title.por.fl_str_mv Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.
dc.title.alternative.eng.fl_str_mv Study of influence of Sm and Er on PbTiO3 ceramics.
title Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.
spellingShingle Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.
Paris, Elaine Cristina
Físico-química
Titanato de chumbo
Terras raras
Método dos precursores polimétricos
Filmes finos
CIENCIAS EXATAS E DA TERRA::QUIMICA
title_short Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.
title_full Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.
title_fullStr Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.
title_full_unstemmed Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.
title_sort Estudo da Influência do Sm e Er em Cerâmicas de PbTiO3.
author Paris, Elaine Cristina
author_facet Paris, Elaine Cristina
author_role author
dc.contributor.authorlattes.por.fl_str_mv http://genos.cnpq.br:12010/dwlattes/owa/prc_imp_cv_int?f_cod=K4700940J8
dc.contributor.author.fl_str_mv Paris, Elaine Cristina
dc.contributor.advisor1.fl_str_mv Leite, Edson Roberto
dc.contributor.advisor1Lattes.fl_str_mv http://genos.cnpq.br:12010/dwlattes/owa/prc_imp_cv_int?f_cod=K4783657E4
dc.contributor.authorID.fl_str_mv 2b06dcbe-d595-48de-ad9e-26077464fa04
contributor_str_mv Leite, Edson Roberto
dc.subject.por.fl_str_mv Físico-química
Titanato de chumbo
Terras raras
Método dos precursores polimétricos
Filmes finos
topic Físico-química
Titanato de chumbo
Terras raras
Método dos precursores polimétricos
Filmes finos
CIENCIAS EXATAS E DA TERRA::QUIMICA
dc.subject.cnpq.fl_str_mv CIENCIAS EXATAS E DA TERRA::QUIMICA
description In this work, it was obtained powders and thin films of (Pb1-xLnx)TiO3, Ln = Sm and Er, using a chemical method of synthesis, polymeric precursor method (Pechini). In this way, the synthesis conditions were optimized in order to minimize the formation of secondary phases. (Pb1-xSmx)TiO3, PST and (Pb1-xErx)TiO3, PET powders, with x varying from 0.01 to 0.1, were obtained in pH 7 and calcined at 600°C for 2 and 8 hours in oxygen atmosphere. There was not formation of secondary phase (pyrochlore) up to 4 mol% of Sm. On the other hand, the solubility limit was already reached at the PbTiO3 (PT) lattice, when doped with 4 mol% of Er. The increase of the percentage of dopants favors the beginning of the tetragonal to cubic phase transition. In this transition, up to 2 mol% of dopants, Er is more efficient than Sm and for above that, an inversion of this behavior occurs. It was observed by micro-Raman spectroscopy and DSC that the addition of Sm or Er to the PT causes a decrease of Curie temperature of the material in relation to the pure PT (~ 490°C). PST and PET thin films were obtained by spin coating on Pt/Ti/SiO2/Si substrate and heat treated at 600°C for 2 hours for the crystallization of the films. It was observed for both PST and PET films are occurring the beginning of the tetragonal to cubic phase transition, resulting in PT with low tetragonality, with the increase of the dopants concentration. It was also verified that these films are textured in the (001) and (100) family plans with both dopants, being a axis direction favored. The obtained films presented nanometric grain sizes and the addition of dopants (Sm or Er) in the PT lattice resulted in a decrease of the average grain size. In order to improving the dielectric and ferroelectric properties of the PST and PET films, it was varied: Sm or Er concentration, number of layers, viscosity of the precursor solution, deposition speed, heat treatment, the bottom electrode and the organic precursor concentration. In the results of electric measurements, it was verified that the Er addition is more efficient than Sm in the increase of the dielectric constant and improvement of ferroelectric properties of the films. It was also observed that the decrease of the tetragonality of the films, with the consequent beginning of the tetragonal to cubic phase transition of the material, there is a reduction of the dielectric constant values and of the remanent polarization for the samples. Using the LaNiO3 like bottom electrode in substitution to the Pt, it was obtained approximated values of dielectric constant, however this substitution resulted in better ferroelectric properties of the films. In spite of obtaining smaller dielectric constant values than those found in the literature, it could be observed that the decrease of the concentration of organic precursors improved the electric properties of the PST and PET films, indicating a dependence relationship of the amount of organic material present in the precursor solution in function of obtaining thin films with satisfactory dielectric and ferroelectric properties.
publishDate 2005
dc.date.issued.fl_str_mv 2005-04-29
dc.date.available.fl_str_mv 2007-07-10
2016-06-02T20:35:05Z
dc.date.accessioned.fl_str_mv 2016-06-02T20:35:05Z
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dc.identifier.citation.fl_str_mv PARIS, Elaine Cristina. Study of influence of Sm and Er on PbTiO3 ceramics.. 2005. 238 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2005.
dc.identifier.uri.fl_str_mv https://repositorio.ufscar.br/handle/ufscar/6353
identifier_str_mv PARIS, Elaine Cristina. Study of influence of Sm and Er on PbTiO3 ceramics.. 2005. 238 f. Tese (Doutorado em Ciências Exatas e da Terra) - Universidade Federal de São Carlos, São Carlos, 2005.
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