Dresden 2009 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 12: Poster II
DF 12.6: Poster
Mittwoch, 25. März 2009, 09:30–12:30, P5
Influence of pressure on the ferroelectric phase transition temperature and domain structure in monoclinic Sn2P2S6 — •Konstantin Rushchanskii1 and Yulian Vysochanskii2 — 1Institut für Festkörperforschung and Institute for Advance Simulation, Forschungszentrum Jülich, D-52425 Jülich, Germany — 2Institute for Solid State Physics and Chemistry, Uzhgorod National University, 54 Voloshyn St., 88000 Uzhgorod, Ukraine
Monoclinic Sn2P2S6 is a proper uniaxal ferroelectric, a promising material for thermal and acoustic transducers as well as for fast holography and nonlinear optics. High polarizability of the chalcogenide anion sublattice and low crystalline symmetry of this compound allow many interesting phenomena such as coexistance of high and low-symmetry phases, low temperature non-Debye dielectric dispersion, displacive vs order-disorder crossover, relaxation processes near transition point, non-linear soft-mode interactions, etc. In our recent work (Phys. Rev. Lett. 99, 207601 (2007)) we developed an ab initio model of the temperature driven phase transition in this crystal, which explains most of the experimentally observed phenomena in this system. Moreover, we have found that a domain wall undergoes transformation between metastable smooth-shape configuration to a stable sharp-shape one at low temperatures of around 60 K. In the present contribution we investigate the influence of temperature and pressure on the structure of domain walls. We will show that smooth-shape domain structure is stabilized by high pressure which affects the pressure dependence of the ferroelectric transition temperature.