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Lattice dynamics in Ba.sub.0.7./sub.Sr.sub.0.3./sub.TiO.sub.3./sub.: study by THz and IR spectroscopy and ab-initio simulations
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SYSNO ASEP 0352308 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Lattice dynamics in Ba0.7Sr0.3TiO3: study by THz and IR spectroscopy and ab-initio simulations Author(s) Ostapchuk, Tetyana (FZU-D) RID, ORCID
Petzelt, Jan (FZU-D) RID, ORCID, SAI
Kužel, Petr (FZU-D) RID, ORCID, SAI
Savinov, Maxim (FZU-D) RID, ORCID
Hlinka, Jiří (FZU-D) RID, ORCID
Tkach, A. (PT)
Vilarinho, P. M. (PT)
Lisenkov, S. (US)
Ponomareva, I. (US)
Bellaiche, L. (US)Source Title Phase Transitions. - : Taylor & Francis - ISSN 0141-1594
Roč. 83, 10-11 (2010), s. 955-965Number of pages 11 s. Language eng - English Country GB - United Kingdom Keywords soft mode ; central mode ; complex dielectric function ; time-domain terahertz spectroscopy ; infrared reflectivity Subject RIV BM - Solid Matter Physics ; Magnetism R&D Projects GAP204/10/0616 GA ČR - Czech Science Foundation (CSF) ME08109 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) CEZ AV0Z10100520 - FZU-D (2005-2011) UT WOS 000284539500022 DOI 10.1080/01411594.2010.509607 Annotation We report on the experimental and theoretical study of the lattice dynamics in Ba0.7Sr0.3TiO3 in 20-900 K temperature range. Complex dielectric response in the terahertz and far infrared range was evaluated from the time-domain THz transmission spectra and infrared reflectivity by means of two damped harmonic oscillator models in classical and factorized form of the dielectric function. The anisotropic dielectric function in the ferroelectric phases was extracted using the Bruggeman model of the effective medium approximation. The fitted parameters of the temperature-dependent Slater-type vibrations (soft and central modes) were compared with those obtained from ab-initio simulations. The role of the lattice phonons and central mode in the dielectric anomaly is discussed. Workplace Institute of Physics Contact Kristina Potocká, potocka@fzu.cz, Tel.: 220 318 579 Year of Publishing 2011
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