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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

SYSNO ASEP	0352308
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Lattice dynamics in Ba_0.7Sr_0.3TiO₃: 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. 955-965
Number 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

Number of the records: 1