Enhancement of tetragonality and role of strontium vacancies in heterovalent doped SrTiO.sub.3./sub..

0359471 - FZÚ 2012 RIV US eng J - Journal Article
Tkach, A. - Almeida, A. - Moreira, J.A. - Correia, T.M. - Chaves, M. R. - Okhay, O. - Vilarinho, P. M. - Gregora, Ivan - Petzelt, Jan
Enhancement of tetragonality and role of strontium vacancies in heterovalent doped SrTiO₃.
Applied Physics Letters. Roč. 98, č. 5 (2011), "052903-1"-"052903-2". ISSN 0003-6951. E-ISSN 1077-3118
R&D Projects: GA AV ČR KAN301370701
Institutional research plan: CEZ:AV0Z10100520
Keywords : strontium titanate * doping * phase transition * Raman spectroscopy
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.844, year: 2011

The effect of Sr vacancies on the behavior of strontium titanate with trivalent dopants (La, Gd, Y) substituting Sr2+ ions is reported. A remarkable shift of the antiferrodistortive transition temperature Ta is revealed by Raman spectroscopy for low content of dopant. A unique linear dependence of Ta on 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, which explains the unexpected increase of lattice parameter with increasing Bi content in (Sr,Bi)TiO₃.
Permanent Link: http://hdl.handle.net/11104/0197256