Phase Diagrams and Domain Splitting in Thin Ferroelectric Films with Incommensurate Phases

Physical review. B, Condensed matter (Impact Factor: 3.66). 12/2009; 81(19). DOI: 10.1103/PhysRevB.81.195437
Source: arXiv


We studied the phase diagram of thin ferroelectric films with incommensurate
phases and semiconductor properties within the framework of
Landau-Ginzburg-Devonshire theory. We performed both analytical calculations
and phase-field modelling of the temperature and thickness dependencies of the
period of incommensurate 180 degree domain structures appeared in thin films
covered with perfect electrodes. It is found that the transition temperature
from the paraelectric into the incommensurate phase as well as the period of
incommensurate domain structure strongly depend on film thickness, and surface
and gradient energy contributions. The results may provide insight on the
temperature dependence of domain structures in nanosized ferroics with inherent
incommensurate phases.

Download full-text


Available from: J.J. Wang
  • [Show abstract] [Hide abstract]
    ABSTRACT: Ferroelectric 180° a-a nanostripe domain structure was observed by transmission electron microscopy in a thin (≤100 nm) film prepared from a bulk single crystal of BaTiO<sub>3</sub> with focused-ion beam (FIB). The domain consists of alternate sequences of narrow and wide anti-parallel domains. High-magnification images of a stable 180° nanoneedle domain, with a sharp tip penetrating into the nanostripe domains, were also obtained. Two-dimensional phase-field simulations based on time-dependent Ginzburg-Landau (TDGL) equations suggest a possibility that such a domain structure is created and stabilized by an in-plane anisotropic stress and an anisotropic mechanical boundary condition of the thin film prepared with FIB.
    No preview · Article · Nov 2010 · IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Relaxor ferroelectrics are a prototypical example of ferroic systems in which interplay between atomic disorder and order parameters gives rise to emergence of unusual properties, including non-exponential relaxations, memory effects, polarization rotations, and broad spectrum of bias- and temperature-induced phase transitions. Despite more than 40 years of extensive research following the original discovery of ferroelectric relaxors by the Smolensky group, the most basic aspect of these materials – the existence and nature of order parameter – has not been understood thoroughly. Using extensive imaging and spectroscopic studies by variable-temperature and time resolved piezoresponse force microscopy, we find that the observed mesoscopic behavior is consistent with the presence of two effective order parameters describing dynamic and static parts of polarization, respectively. The static component gives rise to rich spatially ordered systems on the ∼100 nm length scales, and are only weakly responsive to electric field. The surface of relaxors undergoes a mesoscopic symmetry breaking leading to the freezing of polarization fluctuations and shift of corresponding transition temperature.
    Full-text · Article · Jun 2011 · Advanced Functional Materials
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This work presents the study of domain structure in uniaxial semiconductor ferroelectrics Sn2P2S6, performed by multi-scale theoretical simulations and piezoresponse force microscopy. We reveal that in spite of the second-order ferroelectric phase transition, domain structure contains metastable paraelectric regions between ferroelectric domains after cooling from paraelectric phase to the polar one. Theoretical model shows that this feature is a result of the three-well local potential, which enables metastable non-polar regions in polar environment. We have investigated temperature evolution of the width of non-polar regions in heating-cooling cycle, which is in a good agreement with theoretical results.
    Full-text · Article · Jan 2012 · Ferroelectrics
Show more

Similar Publications