Počet záznamů: 1

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

  1. 1.
    0352308 - FZU-D 2011 RIV GB eng J - Článek v odborném periodiku
    Ostapchuk, Tetyana - Petzelt, Jan - Kužel, Petr - Savinov, Maxim - Hlinka, Jiří - Tkach, A. - Vilarinho, P. M. - Lisenkov, S. - Ponomareva, I. - Bellaiche, L.
    Lattice dynamics in Ba0.7Sr0.3TiO3: study by THz and IR spectroscopy and ab-initio simulations.
    Phase Transitions. Roč. 83, 10-11 (2010), s. 955-965 ISSN 0141-1594
    Grant CEP: GA ČR GAP204/10/0616; GA MŠk ME08109
    Výzkumný záměr: CEZ:AV0Z10100520
    Klíčová slova: soft mode * central mode * complex dielectric function * time-domain terahertz spectroscopy * infrared reflectivity
    Kód oboru RIV: BM - Fyzika pevných látek a magnetismus
    Impakt faktor: 1.006, rok: 2010

    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.
    Trvalý link: http://hdl.handle.net/11104/0191843