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Sr- and Ti-site substitution, lattice dynamics, and octahedral tilt transition relationship in SrTiO3: Mn ceramics / Alexander Tkach in Acta materialia, Vol. 58 N° 2 (Janvier 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 2 (Janvier 2010) . - pp. 577-582 Titre : Sr- and Ti-site substitution, lattice dynamics, and octahedral tilt transition relationship in SrTiO3: Mn ceramics Type de document : texte imprimé Auteurs : Alexander Tkach, Auteur ; Paula M. Vilarinho, Auteur ; Dmitry Nuzhnyy, Auteur Article en page(s) : pp. 577-582 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : SrTiO3  Dopants  Structural  phase  transition  Phonon  dynamics  Infrared  and  terahertz  spectroscopy Index. décimale : 669 Métallurgie Résumé : SrTiO3:Mn ceramics, prepared according to the chemical formulae Sr1–xMnxTiO3 and SrTi1–yMnyO3, are studied by Fourier transform infrared and time-domain terahertz spectroscopy in the temperature range of 10–300 K to support the incorporation of Mn ions into the perovskite lattice of SrTiO3, and to ascertain their different lattice site locations. The polar soft mode of the incipient ferroelectric SrTiO3 is found to be hardened in the whole temperature range by the substitution of Mn ions on Ti sites, and only in the low-temperature range by the Sr site substitution. Activation of the mode, associated with the R point condensation of the Brillouin zone due to the doubling of the unit cell by antiphase rotations of the O-octahedra below the structural transition temperature Ta, shows that the substitution of Mn ions on the Sr sites increases Ta, whereas the Ti-site substitution suppresses Ta with respect to the undoped SrTiO3. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...] [article] Sr- and Ti-site substitution, lattice dynamics, and octahedral tilt transition relationship in SrTiO3: Mn ceramics [texte imprimé] / Alexander Tkach, Auteur ; Paula M. Vilarinho, Auteur ; Dmitry Nuzhnyy, Auteur . - pp. 577-582. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 2 (Janvier 2010) . - pp. 577-582 Mots-clés : SrTiO3  Dopants  Structural  phase  transition  Phonon  dynamics  Infrared  and  terahertz  spectroscopy Index. décimale : 669 Métallurgie Résumé : SrTiO3:Mn ceramics, prepared according to the chemical formulae Sr1–xMnxTiO3 and SrTi1–yMnyO3, are studied by Fourier transform infrared and time-domain terahertz spectroscopy in the temperature range of 10–300 K to support the incorporation of Mn ions into the perovskite lattice of SrTiO3, and to ascertain their different lattice site locations. The polar soft mode of the incipient ferroelectric SrTiO3 is found to be hardened in the whole temperature range by the substitution of Mn ions on Ti sites, and only in the low-temperature range by the Sr site substitution. Activation of the mode, associated with the R point condensation of the Brillouin zone due to the doubling of the unit cell by antiphase rotations of the O-octahedra below the structural transition temperature Ta, shows that the substitution of Mn ions on the Sr sites increases Ta, whereas the Ti-site substitution suppresses Ta with respect to the undoped SrTiO3. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235556%23 [...]