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Information × Registration Number 0211U008927, 0111U007245 , R & D reports Title Novel Approaches for Probing Ferroelectric Domain Wall Structure and Local Dynamics on the Nanoscale popup.stage_title Теоретичне дослідження нових типів сегнетоелектричних доменних стінок, що нагадують феромагнітні стінки Блоха та Нееля, в гетероструктурах та багатошарових плівках Head Svechnikov Sergei Vasil'evich, Registration Date 30-11-2011 Organization Institute of Semiconductor Physics of National Academy of Sciences of Ukrain popup.description2 Theoretical analysis based on the Landau-Ginzburg-Devonshire (LGD) theory is used to show that the product effect of flexoelectricity and rotostriction can lead to a spontaneous polarization in the vicinity of antiphase boundaries, ferroelastic twin walls, surfaces and interfaces in the octahedrally tilted phase of otherwise non-ferroelectric perovskites such as CaTiO3, SrTiO3, and EuTiO3.. As an example, we numerically demonstrate a large spontaneous polarization on the order of 1-5 C/cm2 at the SrTiO3 antidistortive phase boundaries at temperatures lower than the antiferrodistortive structural phase transition temperature of ~105 K in agreement with previously unexplained experimental results. Using Landau-Ginsburg Devonshire approach we calculate the impact of the misfit strain, interface energy, finite size effects on the phase diagram, polar properties and hysteresis loops of the multilayers ferroelectric BaTiO3/ incipient ferroelectric SrTiO3. For the first time the impact of the elastic strain between the thin film and substrate originated from the lattice constants misfit on phase diagram of multilyers SrTiO3/ BaTiO3 was investigated. We show that 6 thermodynamically stable phases (paraelectric, tetragonal FEc, 2 monoclinic FEaac and FEac, 2 orthorhombic FEa and FEaa ferroelectric phases) can exist in such multilayers, in contrast to the bulk BaTiO3, where only 4 phases (paraelectric, tetragonal, orthorhombic and rhombohedral) are stable. We calculate the basic polar properties of hysteresis loops (shape, coercive field and spontaneous polarization) in the thin SrTiO3/BaTiO3 multilayers. It was shown, that the strong dependence of polar properties on the thickness SrTiO3 and BaTiO3 layers, elastic misfit strain exists in such system. Moreover SrTiO3 plays a role of dielectric gap: the bigger is the gap thickness the stronger is depolarization fields, which in turn decreases the spontaneous polarization of the BaTiO3 film. Product Description popup.authors Єлісєєв Євген Анатолійович Морозовська Ганна Миколаївна Свєчніков Георгій Сергійович Свєчніков Сергій Васильович popup.nrat_date 2020-04-02 Close