Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics
Autor(a) principal: | |
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Data de Publicação: | 2021 |
Outros Autores: | , , , , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UNESP |
Texto Completo: | http://dx.doi.org/10.1016/j.jallcom.2020.158320 http://hdl.handle.net/11449/207168 |
Resumo: | Polycrystalline MnO:ZnO bulk ceramics with a Mn proportion of 6, 11, 17 and 22 at% are prepared through a solid-state reaction and subjected to a heat treatment in a reducing atmosphere (Ar (95%) and H2 (5%)). The samples are studied with particular emphasis on their composition and structural and magnetic properties. A detailed microstructural and chemical analysis confirms the Mn doping of the wurtzite ZnO structure mainly at the surface of the ZnO grains. For the samples with higher Mn proportions, the secondary phases ZnMn2O4 and Mn1−xZnxO (Zn-doped MnO) are detected for the as-prepared and heat-treated samples, respectively. The structural change of the secondary phases under heat treatment, from ZnMn2O4 to Mn1−xZnxO, confirms the effectiveness of the heat treatment in reducing the valence of the Mn ions and in the formation of oxygen vacancies into the system. In spite of the induced defects, the magnetic analysis presents only a paramagnetic behavior with an antiferromagnetic coupling between the Mn ions. In the context of the bound magnetic polaron theory, it is concluded that oxygen vacancies are not the necessary defect to promote the desired ferromagnetic order at room temperature. |
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Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramicsDefect engineeringMultifunctionalitySpintronicsZinc oxidePolycrystalline MnO:ZnO bulk ceramics with a Mn proportion of 6, 11, 17 and 22 at% are prepared through a solid-state reaction and subjected to a heat treatment in a reducing atmosphere (Ar (95%) and H2 (5%)). The samples are studied with particular emphasis on their composition and structural and magnetic properties. A detailed microstructural and chemical analysis confirms the Mn doping of the wurtzite ZnO structure mainly at the surface of the ZnO grains. For the samples with higher Mn proportions, the secondary phases ZnMn2O4 and Mn1−xZnxO (Zn-doped MnO) are detected for the as-prepared and heat-treated samples, respectively. The structural change of the secondary phases under heat treatment, from ZnMn2O4 to Mn1−xZnxO, confirms the effectiveness of the heat treatment in reducing the valence of the Mn ions and in the formation of oxygen vacancies into the system. In spite of the induced defects, the magnetic analysis presents only a paramagnetic behavior with an antiferromagnetic coupling between the Mn ions. In the context of the bound magnetic polaron theory, it is concluded that oxygen vacancies are not the necessary defect to promote the desired ferromagnetic order at room temperature.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de Ouro Preto – UFOPDepartamento de Física Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista – UNESPDepartamento de Física Universidade Federal de São Carlos – UFSCarInstituto de Física Universidade de São Paulo – USPUniversidade Federal de Alfenas – UNIFALDepartamento de Física Instituto de Geociências e Ciências Exatas Universidade Estadual Paulista – UNESPFAPESP: 07/56231-0FAPESP: 2015/16191-5CNPq: 306715/2018-0Universidade Federal de Ouro Preto – UFOPUniversidade Estadual Paulista (Unesp)Universidade Federal de São Carlos (UFSCar)Universidade de São Paulo (USP)Universidade Federal de Alfenas – UNIFALLage, V.M. Almeidada Silva, R. T.Mesquita, A. [UNESP]de Godoy, M. P.F.Gratens, X.Chitta, V. A.de Carvalho, H. B.2021-06-25T10:50:04Z2021-06-25T10:50:04Z2021-05-15info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://dx.doi.org/10.1016/j.jallcom.2020.158320Journal of Alloys and Compounds, v. 863.0925-8388http://hdl.handle.net/11449/20716810.1016/j.jallcom.2020.1583202-s2.0-85099719123Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengJournal of Alloys and Compoundsinfo:eu-repo/semantics/openAccess2021-10-23T16:22:43Zoai:repositorio.unesp.br:11449/207168Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestopendoar:29462024-08-05T20:34:10.281736Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false |
dc.title.none.fl_str_mv |
Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics |
title |
Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics |
spellingShingle |
Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics Lage, V.M. Almeida Defect engineering Multifunctionality Spintronics Zinc oxide |
title_short |
Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics |
title_full |
Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics |
title_fullStr |
Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics |
title_full_unstemmed |
Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics |
title_sort |
Influence of reducing heat treatment on the structural and magnetic properties of MnO:ZnO ceramics |
author |
Lage, V.M. Almeida |
author_facet |
Lage, V.M. Almeida da Silva, R. T. Mesquita, A. [UNESP] de Godoy, M. P.F. Gratens, X. Chitta, V. A. de Carvalho, H. B. |
author_role |
author |
author2 |
da Silva, R. T. Mesquita, A. [UNESP] de Godoy, M. P.F. Gratens, X. Chitta, V. A. de Carvalho, H. B. |
author2_role |
author author author author author author |
dc.contributor.none.fl_str_mv |
Universidade Federal de Ouro Preto – UFOP Universidade Estadual Paulista (Unesp) Universidade Federal de São Carlos (UFSCar) Universidade de São Paulo (USP) Universidade Federal de Alfenas – UNIFAL |
dc.contributor.author.fl_str_mv |
Lage, V.M. Almeida da Silva, R. T. Mesquita, A. [UNESP] de Godoy, M. P.F. Gratens, X. Chitta, V. A. de Carvalho, H. B. |
dc.subject.por.fl_str_mv |
Defect engineering Multifunctionality Spintronics Zinc oxide |
topic |
Defect engineering Multifunctionality Spintronics Zinc oxide |
description |
Polycrystalline MnO:ZnO bulk ceramics with a Mn proportion of 6, 11, 17 and 22 at% are prepared through a solid-state reaction and subjected to a heat treatment in a reducing atmosphere (Ar (95%) and H2 (5%)). The samples are studied with particular emphasis on their composition and structural and magnetic properties. A detailed microstructural and chemical analysis confirms the Mn doping of the wurtzite ZnO structure mainly at the surface of the ZnO grains. For the samples with higher Mn proportions, the secondary phases ZnMn2O4 and Mn1−xZnxO (Zn-doped MnO) are detected for the as-prepared and heat-treated samples, respectively. The structural change of the secondary phases under heat treatment, from ZnMn2O4 to Mn1−xZnxO, confirms the effectiveness of the heat treatment in reducing the valence of the Mn ions and in the formation of oxygen vacancies into the system. In spite of the induced defects, the magnetic analysis presents only a paramagnetic behavior with an antiferromagnetic coupling between the Mn ions. In the context of the bound magnetic polaron theory, it is concluded that oxygen vacancies are not the necessary defect to promote the desired ferromagnetic order at room temperature. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-06-25T10:50:04Z 2021-06-25T10:50:04Z 2021-05-15 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://dx.doi.org/10.1016/j.jallcom.2020.158320 Journal of Alloys and Compounds, v. 863. 0925-8388 http://hdl.handle.net/11449/207168 10.1016/j.jallcom.2020.158320 2-s2.0-85099719123 |
url |
http://dx.doi.org/10.1016/j.jallcom.2020.158320 http://hdl.handle.net/11449/207168 |
identifier_str_mv |
Journal of Alloys and Compounds, v. 863. 0925-8388 10.1016/j.jallcom.2020.158320 2-s2.0-85099719123 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
Journal of Alloys and Compounds |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.source.none.fl_str_mv |
Scopus reponame:Repositório Institucional da UNESP instname:Universidade Estadual Paulista (UNESP) instacron:UNESP |
instname_str |
Universidade Estadual Paulista (UNESP) |
instacron_str |
UNESP |
institution |
UNESP |
reponame_str |
Repositório Institucional da UNESP |
collection |
Repositório Institucional da UNESP |
repository.name.fl_str_mv |
Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP) |
repository.mail.fl_str_mv |
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1808129221163220992 |