resumo
Structural, dielectric and magnetic properties of dense Dy-substituted strontium titanate ceramics are investigated. In the Sr1-1.5xDyxTiO3 system, incorporation of Dy onto the Sr site is confirmed by a linear decrease of the lattice parameter up to x = 0.05. Dielectric spectroscopy analysis of Sr1-1.5xDyxTiO3 ceramics reveals four relaxations. Two relaxations observed below 55 K are attributed to dipoles formed by off-centre displacement of Dy3+ ions on the Sr sites. Other two dielectric relaxations found at higher temperatures are attributed to the oxygen vacancy related mechanisms. As result, very high dielectric permittivity of similar to 33500 at 28 K and of similar to 9600 around room temperature at moderate dissipation factor of similar to 0.02 are obtained for Sr0 985DY0.01TiO3 ceramics, making it a promising material for capacitor electronic applications. Paramagnetic behaviour observed for Sr1-1.5xDyxTiO3 as well as for Sr1-xDy2xTi1-xO3 ceramics indicates impossibility to induce a magnetic order and hence magnetoelectric coupling in strontium titanate by Dy substitution.
palavras-chave
SRTIO3; RELAXATION
categoria
Materials Science
autores
Tkach, A; Amaral, JS; Zlotnik, S; Amaral, VS; Vilarinho, PM
nossos autores
João Cunha de Sequeira Amaral
Investigador Auxiliar
Oleksandr Tkach
Investigador Auxiliar
Paula Maria Lousada Silveirinha Vilarinho
Vice-Diretor
Sebastian Zlotnik
Bolseiro de pós-Doutoramento
Vitor Brás Sequeira Amaral
Professor CatedráticoProjectos
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Projeto de Investigação Exploratória: João Amaral (IF/01089/2015)
RMNE-UA-National Network of Electron Microscopy (REDE/1509/RME/2005 )
agradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement as well as within FCT independent researcher grants IF/00602/2013 (A. Tkach) and IF/01089/2015 (J. S. Amaral). SEM/EDS characterization was supported by the project REDE/1509/RME/2005.