High-temperature antiferroelectric and ferroelectric phase transitions in phase pure LaTaO4.

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MetadadosDescriçãoIdioma
Autor(es): dc.creatorAbreu, Yuslín Gonzále-
Autor(es): dc.creatorSiqueira, Kisla Prislen Félix-
Autor(es): dc.creatorMatinaga, Franklin Massami-
Autor(es): dc.creatorMoreira, Roberto Luiz-
Autor(es): dc.creatorDias, Anderson-
Data de aceite: dc.date.accessioned2025-08-21T15:51:38Z-
Data de disponibilização: dc.date.available2025-08-21T15:51:38Z-
Data de envio: dc.date.issued2018-03-13-
Data de envio: dc.date.issued2018-03-13-
Data de envio: dc.date.issued2017-
Fonte completa do material: dc.identifierhttp://www.repositorio.ufop.br/handle/123456789/9590-
Fonte completa do material: dc.identifierhttps://doi.org/10.1016/j.ceramint.2016.10.128-
Fonte: dc.identifier.urihttp://educapes.capes.gov.br/handle/capes/1025991-
Descrição: dc.descriptionPhase-pure LaTaO4 ceramics was prepared by solid-state reaction. Dielectric spectroscopic data as well as differential scanning calorimetric experiments showed the existence of a sequence two high-temperature firstorder structural phase transitions. The first phase transition occurs above 160 °C (on heating), from the monoclinic P21/c space group at room temperature to the polar orthorhombic Cmc21 group, exhibiting a very large thermal hysteresis probably linked to the reconstructive nature of the structural transition. The second transition occurs around 225 °C to the orthorhombic Cmcm space group, with a small thermal hysteresis. Vibrational Raman spectroscopic analyses confirmed these two sequential phase transitions, as well as the thermal hysteresis observed for both first-order transitions in repeated heating and cooling cycles. The existence of a strong monoclinic distortion at room temperature could be related to the presence of defects (oxygen vacancies) in LaTaO4 ceramics, after sintering. Dielectric spectroscopy showed a strong influence of the electric conductivity on the dielectric response with activation energy of dc component of conductivity (0.62 eV) compatible with the presence of oxygen vacancies. Far-infrared data confirmed that the extra modes observed in the Raman spectra are forbidden bands, which were activated by defects into the structure.-
Formato: dc.formatapplication/pdf-
Idioma: dc.languageen-
Direitos: dc.rightsaberto-
Direitos: dc.rightsO periódico Ceramics International concede permissão para depósito deste artigo no Repositório Institucional da UFOP. Número da licença: 4210810499454.-
Palavras-chave: dc.subjectFerroelectrics-
Palavras-chave: dc.subjectPhase transitions-
Palavras-chave: dc.subjectDielectrics-
Palavras-chave: dc.subjectVibrational spectroscopy-
Título: dc.titleHigh-temperature antiferroelectric and ferroelectric phase transitions in phase pure LaTaO4.-
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