Enhancement of tetragonality and role of strontium vacancies in heterovalent doped SrTiO3

authors	Tkach, A; Almeida, A; Moreira, JA; Correia, TM; Chaves, MR; Okhay, O; Vilarinho, PM; Gregora, I; Petzelt, J
nationality	International
journal	APPLIED PHYSICS LETTERS
keywords	PHASE-TRANSITION
abstract	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]
publisher	AMER INST PHYSICS
issn	0003-6951
year published	2011
volume	98
issue	5
digital object identifier (doi)	10.1063/1.3549181
web of science category	Physics, Applied
subject category	Physics
unique article identifier	WOS:000286988400050