1. Enhancement of tetragonality and role of strontium vacancies in heterovalent doped SrTiO3.
- Author
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Tkach, A., Almeida, A., Moreira, J. Agostinho, Correia, T. M., Chaves, M. R., Okhay, O., Vilarinho, P. M., Gregora, I., and Petzelt, J.
- Subjects
STRONTIUM ,RAMAN spectroscopy ,FERROELECTRICITY ,PEROVSKITE ,PHASE transitions ,DIELECTRICS ,BRILLOUIN scattering - Abstract
The effect of Sr vacancies on the behavior of strontium titanate with trivalent dopants (La
3+ , Gd3+ , and Y3+ ) substituting Sr2+ ions is reported. A remarkable shift of the antiferrodistortive transition temperature Ta 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 ∼1.54 Å is estimated, which is ∼7% larger than Sr2+ radius. This size difference enables explaining the unexpected increase of lattice parameter with increasing Bi3+ content in Sr1-1.5x Bix TiO3 . [ABSTRACT FROM AUTHOR]- Published
- 2011
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