Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión
Ano de defesa: | 2014 |
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Autor(a) principal: | |
Orientador(a): | |
Banca de defesa: | , , , , |
Tipo de documento: | Tese |
Tipo de acesso: | Acesso aberto |
Idioma: | por |
Instituição de defesa: |
Universidade Federal de Goiás
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Programa de Pós-Graduação: |
Programa de Pós-graduação em Fisica (IF)
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Departamento: |
Instituto de Física - IF (RG)
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País: |
Brasil
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Palavras-chave em Português: | |
Área do conhecimento CNPq: | |
Link de acesso: | http://repositorio.bc.ufg.br/tede/handle/tede/4430 |
Resumo: | This work describes the synthesis of yttrium orthochromite polycrystalline YCrO3 by two different methods: modified polymeric precursor (MPP) and solution combustion (SC) and with additional heat treatment at 1300 °C. Were analyzed the effect of these two methods as well as the effect of additional thermal treatment of the samples prepared by the combustion method, on the physical properties of YCrO3 by several spectroscopic and structural techniques: X-ray diffraction (XRD), scanning electron microscopy and transmission (SEM and TEM), Fourier transform spectroscopy and infrared, diffuse reflectance, susceptibility and electron paramagnetic resonance (EPR). Images (SEM) show that the powders YCrO3 synthesized by the two methods of synthesis have similar morphologies, with average grain size of approximately 160 nm. Through the images was found that applying heat treatment to the sample obtained by combustion synthesis at the same temperature as the precursor obtained by the polymeric precursor method, the structural characteristics of the material are similar. The spectra diffuse reflectance of the different samples exhibit two intense bands, which correspond to electronic transitions of ion Cr3+ from the ground state 4A2g to the excited states, 4A2g → 4T2g and 4A2g → 4T1g two minor bands corresponding to the transitions 4A2g → 2Eg and 4A2g → 2T1g were observed in the spectra. Were calculated from the spectra the crystal field parameters Dq and Racah, B and C for all samples, with average values of 3.03 for Dq, 542 cm-1 and 3,144 cm-1 for B and C respectively. Even with these spectra and the theory of Kubelka-Munk was calculate the optical gap Eg, with a mean value of 3.7 eV, coinciding with those reported in the literature for YCrO3 prepared by other methods. The dependence of the spectrum parameters (EPR), factor g, intensity, and line width as a function of temperature was also studied from 100 K to 300 K. The results show that, near 140 K, the Néel temperature for the material, a magnetic phase transition occurs from the antiferromagnetic phase to the paramagnetic phase, in full agreement with the results obtained from measurements of susceptibility. Our results are discussed and compared with other reported in the literature. |
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Santana, Ricardo Costa dehttp://lattes.cnpq.br/5179092743729595Carvalho, Jesiel FreitasSantana, Ricardo Costa deCarvalho, Jesiel FreitasAraújo, Eudes Borges dePrado, Rogério JunqueiraBufaiçal, Leandro Felix de Sousahttp://lattes.cnpq.br/6977127728325491Jara, Antonio Nolberto Lazo2015-04-20T13:35:20Z2014-04-23JARA, A. N. L. Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión. 2014. 67 f. Tese (Doutorado em Fisica) - Universidade Federal de Goiás, Goiânia, 2014.http://repositorio.bc.ufg.br/tede/handle/tede/4430This work describes the synthesis of yttrium orthochromite polycrystalline YCrO3 by two different methods: modified polymeric precursor (MPP) and solution combustion (SC) and with additional heat treatment at 1300 °C. Were analyzed the effect of these two methods as well as the effect of additional thermal treatment of the samples prepared by the combustion method, on the physical properties of YCrO3 by several spectroscopic and structural techniques: X-ray diffraction (XRD), scanning electron microscopy and transmission (SEM and TEM), Fourier transform spectroscopy and infrared, diffuse reflectance, susceptibility and electron paramagnetic resonance (EPR). Images (SEM) show that the powders YCrO3 synthesized by the two methods of synthesis have similar morphologies, with average grain size of approximately 160 nm. Through the images was found that applying heat treatment to the sample obtained by combustion synthesis at the same temperature as the precursor obtained by the polymeric precursor method, the structural characteristics of the material are similar. The spectra diffuse reflectance of the different samples exhibit two intense bands, which correspond to electronic transitions of ion Cr3+ from the ground state 4A2g to the excited states, 4A2g → 4T2g and 4A2g → 4T1g two minor bands corresponding to the transitions 4A2g → 2Eg and 4A2g → 2T1g were observed in the spectra. Were calculated from the spectra the crystal field parameters Dq and Racah, B and C for all samples, with average values of 3.03 for Dq, 542 cm-1 and 3,144 cm-1 for B and C respectively. Even with these spectra and the theory of Kubelka-Munk was calculate the optical gap Eg, with a mean value of 3.7 eV, coinciding with those reported in the literature for YCrO3 prepared by other methods. The dependence of the spectrum parameters (EPR), factor g, intensity, and line width as a function of temperature was also studied from 100 K to 300 K. The results show that, near 140 K, the Néel temperature for the material, a magnetic phase transition occurs from the antiferromagnetic phase to the paramagnetic phase, in full agreement with the results obtained from measurements of susceptibility. Our results are discussed and compared with other reported in the literature.Neste trabalho descreve-se a síntese da ortocromita de ítrio YCrO3 policristalina por dois diferentes métodos: precursores polímericos modificado (MPP) e combustão em solução (CS) com e sem tratamento térmico adicional à 1300 °C. O efeito desses dois métodos, bem como o efeito do tratamento térmico adicional às amostras preparadas pelo método de combustão, foram analizados as propriedades físicas do YCrO3 por diversas técnicas espectroscópicas e estruturais: difracção de raios-X (DRX), microscopia eletronica de varredura e transmissão (MEV e MET), espectroscopias de transformada de Fourier no infravermelho e de reflectância difusa, susceptibilidade e ressonância paramagnética eletrônica (RPE). As imagens (MEV) mostram que os pós de YCrO3 sintetizados através dos dois métodos de síntese possuem morfologias semelhantes, com tamanho médio de grãos de aproximadamente 160 nm. Através das imagens foi constatado que a aplicação de um tratamento térmico para a amostra obtida por combustão, na mesma temperatura síntese que a obtida pelo método de precursores de polímericos, não alteran significativamente as propriedades estructurais do sistema. Os espectros de reflectância difusa das diferentes amostras apresentam duas bandas intensas, as quais correspondem às transições eletrônicas do ion Cr3+ desde o estado fundamental 4A2g para os estados excitados 4T2g e 4T1g. Duas bandas menores correspondentes às transições 4A2g → 2Eg e 4A2g → 2T1g também puderam ser observadas nos espectros. A partir dos espectros foram calculados os parâmetros de campo cristalino Dq e de Racah, B e C, para todas as amostras, com valores médios de 3.03 para Dq, 542 cm-1 e 3.144 cm-1 para B e C respectivamente. Ainda com estes espectros e a teoria de Kubelka-Munk calculamos o gap óptico Eg, com valor médio de 3,7 eV, coincidindo com os reportados na literatura para o YCrO3 preparado por outros métodos. Também foi estudada a dependência dos parâmetros do espectro de RPE, fator g, intensidade e largura de linha em função da temperatura, desde 100 K até 300 K. Os resultados mostram que, próximo de 140 K, temperatura de Néel para este material, ocorre uma transição de fase magnética, desde a fase antiferromagnética para a fase paramagnética, em pleno acordo com os resultados obtidos através das medidas de susceptibilidade. Os nossos resultados são discutidos e comparados com outros reportados na literatura.Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2015-04-20T13:31:52Z No. of bitstreams: 3 Tese - Antonio Nolberto Lazo Jara - 2014 (1).pdf: 19921321 bytes, checksum: 3dbe9575780ee667750eed905d7005ca (MD5) Tese - Antonio Nolberto Lazo Jara - 2014 (2).pdf: 2545791 bytes, checksum: e61a5317d7594ea62471c3b38128a69d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-04-20T13:35:20Z (GMT) No. of bitstreams: 3 Tese - Antonio Nolberto Lazo Jara - 2014 (1).pdf: 19921321 bytes, checksum: 3dbe9575780ee667750eed905d7005ca (MD5) Tese - Antonio Nolberto Lazo Jara - 2014 (2).pdf: 2545791 bytes, checksum: e61a5317d7594ea62471c3b38128a69d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5)Made available in DSpace on 2015-04-20T13:35:20Z (GMT). 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dc.title.por.fl_str_mv |
Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión |
title |
Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión |
spellingShingle |
Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión Jara, Antonio Nolberto Lazo Ortocromita de ítrio, YCrO3 Método precursores poliméricos modificado Método de combustão em solução EPR, transição magnética CIENCIAS EXATAS E DA TERRA::FISICA |
title_short |
Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión |
title_full |
Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión |
title_fullStr |
Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión |
title_full_unstemmed |
Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión |
title_sort |
Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión |
author |
Jara, Antonio Nolberto Lazo |
author_facet |
Jara, Antonio Nolberto Lazo |
author_role |
author |
dc.contributor.advisor1.fl_str_mv |
Santana, Ricardo Costa de |
dc.contributor.advisor1Lattes.fl_str_mv |
http://lattes.cnpq.br/5179092743729595 |
dc.contributor.advisor-co1.fl_str_mv |
Carvalho, Jesiel Freitas |
dc.contributor.referee1.fl_str_mv |
Santana, Ricardo Costa de |
dc.contributor.referee2.fl_str_mv |
Carvalho, Jesiel Freitas |
dc.contributor.referee3.fl_str_mv |
Araújo, Eudes Borges de |
dc.contributor.referee4.fl_str_mv |
Prado, Rogério Junqueira |
dc.contributor.referee5.fl_str_mv |
Bufaiçal, Leandro Felix de Sousa |
dc.contributor.authorLattes.fl_str_mv |
http://lattes.cnpq.br/6977127728325491 |
dc.contributor.author.fl_str_mv |
Jara, Antonio Nolberto Lazo |
contributor_str_mv |
Santana, Ricardo Costa de Carvalho, Jesiel Freitas Santana, Ricardo Costa de Carvalho, Jesiel Freitas Araújo, Eudes Borges de Prado, Rogério Junqueira Bufaiçal, Leandro Felix de Sousa |
dc.subject.por.fl_str_mv |
Ortocromita de ítrio, YCrO3 Método precursores poliméricos modificado Método de combustão em solução EPR, transição magnética |
topic |
Ortocromita de ítrio, YCrO3 Método precursores poliméricos modificado Método de combustão em solução EPR, transição magnética CIENCIAS EXATAS E DA TERRA::FISICA |
dc.subject.cnpq.fl_str_mv |
CIENCIAS EXATAS E DA TERRA::FISICA |
description |
This work describes the synthesis of yttrium orthochromite polycrystalline YCrO3 by two different methods: modified polymeric precursor (MPP) and solution combustion (SC) and with additional heat treatment at 1300 °C. Were analyzed the effect of these two methods as well as the effect of additional thermal treatment of the samples prepared by the combustion method, on the physical properties of YCrO3 by several spectroscopic and structural techniques: X-ray diffraction (XRD), scanning electron microscopy and transmission (SEM and TEM), Fourier transform spectroscopy and infrared, diffuse reflectance, susceptibility and electron paramagnetic resonance (EPR). Images (SEM) show that the powders YCrO3 synthesized by the two methods of synthesis have similar morphologies, with average grain size of approximately 160 nm. Through the images was found that applying heat treatment to the sample obtained by combustion synthesis at the same temperature as the precursor obtained by the polymeric precursor method, the structural characteristics of the material are similar. The spectra diffuse reflectance of the different samples exhibit two intense bands, which correspond to electronic transitions of ion Cr3+ from the ground state 4A2g to the excited states, 4A2g → 4T2g and 4A2g → 4T1g two minor bands corresponding to the transitions 4A2g → 2Eg and 4A2g → 2T1g were observed in the spectra. Were calculated from the spectra the crystal field parameters Dq and Racah, B and C for all samples, with average values of 3.03 for Dq, 542 cm-1 and 3,144 cm-1 for B and C respectively. Even with these spectra and the theory of Kubelka-Munk was calculate the optical gap Eg, with a mean value of 3.7 eV, coinciding with those reported in the literature for YCrO3 prepared by other methods. The dependence of the spectrum parameters (EPR), factor g, intensity, and line width as a function of temperature was also studied from 100 K to 300 K. The results show that, near 140 K, the Néel temperature for the material, a magnetic phase transition occurs from the antiferromagnetic phase to the paramagnetic phase, in full agreement with the results obtained from measurements of susceptibility. Our results are discussed and compared with other reported in the literature. |
publishDate |
2014 |
dc.date.issued.fl_str_mv |
2014-04-23 |
dc.date.accessioned.fl_str_mv |
2015-04-20T13:35:20Z |
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info:eu-repo/semantics/publishedVersion |
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doctoralThesis |
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publishedVersion |
dc.identifier.citation.fl_str_mv |
JARA, A. N. L. Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión. 2014. 67 f. Tese (Doutorado em Fisica) - Universidade Federal de Goiás, Goiânia, 2014. |
dc.identifier.uri.fl_str_mv |
http://repositorio.bc.ufg.br/tede/handle/tede/4430 |
identifier_str_mv |
JARA, A. N. L. Síntesis y propiedades ópticas y magnéticas del ycro3 preparado por los métodos precursor polimérico modificado y reacción de combustión. 2014. 67 f. Tese (Doutorado em Fisica) - Universidade Federal de Goiás, Goiânia, 2014. |
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http://repositorio.bc.ufg.br/tede/handle/tede/4430 |
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por |
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http://creativecommons.org/licenses/by-nc-nd/4.0/ info:eu-repo/semantics/openAccess |
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http://creativecommons.org/licenses/by-nc-nd/4.0/ |
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openAccess |
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application/pdf |
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Universidade Federal de Goiás |
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Programa de Pós-graduação em Fisica (IF) |
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UFG |
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Brasil |
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Instituto de Física - IF (RG) |
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Universidade Federal de Goiás |
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Repositório Institucional da UFG |
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