resumo
The effect of Sr vacancies on the behavior of strontium titanate with trivalent dopants (La3+, Gd3+, and Y3+) substituting Sr2+ ions is reported. A remarkable shift of the antiferrodistortive transition temperature T-a is revealed by Raman spectroscopy for just a small content of dopant. It is shown that a unique linear dependence of Ta versus tolerance factor is obtained when Sr-vacancies are taken into account. A vacancy size value of similar to 1.54 angstrom is estimated, which is similar to 7% larger than Sr2+ radius. This size difference enables explaining the unexpected increase of lattice parameter with increasing Bi3+ content in Sr1-1.5xBixTiO3. (C) 2011 American Institute of Physics. [doi:10.1063/1.3549181]
palavras-chave
PHASE-TRANSITION
categoria
Physics
autores
Tkach, A; Almeida, A; Moreira, JA; Correia, TM; Chaves, MR; Okhay, O; Vilarinho, PM; Gregora, I; Petzelt, J
nossos autores
Oleksandr Tkach
Investigador
Olena Okhay
Bolseiro de pós-Doutoramento
Paula Maria Lousada Silveirinha Vilarinho
Vice-DiretorProjectos
Propriedades dieléctricas e dinânica da rede de materiais granulantes (POCTI/CTM/45284/2002)
agradecimentos
This work was supported by the Portuguese Foundation for Science and Technology FCT (Project POCTI/CTM/45284/2002, Scholarship No. SFRH/BPD/34607/2007), Academy of Sciences of the Czech Republic (Project No. KAN301370701), and Science Foundation of the Czech Republic (Project No. AVOZ10100520)