Showing papers by "Yoshihiro Ishibashi published in 2003"
TL;DR: In this article, double-layer ferroelectrics comprising two distinct layers of different polarization properties, with bilinear interface coupling across the interface, are examined analytically within the framework of Landau-Ginzburg phenomenological theory.
Abstract: Interface structures in double-layer ferroelectrics comprising two distinct layers of different polarization properties, with bilinear interface coupling across the interface, are examined analytically within the framework of Landau–Ginzburg phenomenological theory The structures are investigated for coupled layers with: (i) one layer in paraelectric phase and the other in ferroelectric phase (ferroelectric–paraelectric), and (ii) both layers in ferroelectric phases (ferroelectric–ferroelectric) The effects of interfacial coupling on the total interface structure energies, interfacial coupling energies and mismatch in polarization across the interface are discussed
33 citations
TL;DR: In this article, it is shown that phase transitions in a recently discovered class of hydrogen-bonded organic crystals are analyzed by Landau theory and shown that the transitions are ferroelastic.
23 citations
TL;DR: In this paper, the authors showed that both the 90° and 180° domain wall structures on the etched surface of the PZN-xPT can be observed using SPM.
Abstract: Domain wall structures on the etched surfaces of the solid solutions of Pb(Zn1/3Nb2/3)O3–xPbTiO3 (PZN-xPT; x≤20%) were investigated by scanning probe microscopy (SPM). We showed that both the 90° and 180° domain wall structures on the etched surface of the PZN-xPT (x=10–20%) can be observed using SPM. We found that complex 180° domain wall structures with a typical size on the 1–2 µm order exist in the c-domain on the (001)-crystal surface of PZN-20%PT. A fingerprint pattern was found on PZN-xPT (x≤8%). It is found that no ferroelastic domain wall structure is observed in the concentration range below x=5%.
22 citations
TL;DR: In this paper, the effects of dc electric field on the domain configuration and permittivity of the rhombohedral (110) 0.69PIN-0.31 plate were simultaneously investigated.
Abstract: Domain observation in Pb(In1/2Nb1/2)O3–PbTiO3[PIN-PT] solid-solution single crystals near the morphotropic phase boundary (MPB) was carried out by polarized light microscopy. The rhombohedral (R)-to-tetragonal (T) phase transition began to take place abruptly in the (110) plane at about 6 kV/cm in the rhombohedral (001) 0.72PIN-0.28PT plate with the dc electric field applied along the direction. The phase boundary between the R and T phases along the (110) plane approached the R region at the expense of the R region, and the R and T phases coexisted in a wide dc field range from 6 kV/cm to 12 kV/cm. The electric-field-induced R-to-T phase transition was very diffuse. The (110) plane plays an important role in this phase transition. The effects of the dc electric field on the domain configuration and permittivity of the rhombohedral (110) 0.69PIN-0.31PT plate were simultaneously investigated, and the contributions of the 109° and 71° polarization configurations to permittivity were discussed on the basis of the Ishibashi theory.
11 citations
TL;DR: A simple electrostatic model for ferroelectric films with an a-domain variant embedded up to a given fraction in a c-domain, based on the electrostatics of inhomogeneous Ferroelectric systems with anisotropic properties, was proposed in this article.
Abstract: We propose a simple electrostatic model for ferroelectric films with an a-domain variant embedded up to a given fraction in a c-domain, based on the electrostatics of inhomogeneous ferroelectric systems with anisotropic properties. The practical aim of this study is to establish the dielectric permittivity dependence on a- or c-domain fraction and compare it with experimental results. The dielectric permittivity is calculated intrinsically by averaging the electrostatic contributions from a- and c-domain variants. Subsequently, analytical approximations for the electric potential and dielectric permittivity are obtained from an equivalent circuit analysis and conclusions are drawn with respect to fitting of real data with simple model relationships.
10 citations
TL;DR: A generalized thermodynamic theory for ferroelectric thin films undergoing second order phase transition is developed in this paper via the concept of extrapolation length δ in the Tilley-Zeks model.
Abstract: A generalized thermodynamic theory (effective Landau–Devonshire-type theory) for ferroelectric thin films undergoing second order phase transition is developed within the framework of the Landau–Ginzburg theory via the concept of extrapolation length δ in the Tilley–Zeks model. The free energy of the Tilley–Zeks model for ferroelectric thin films is cast into a clearer and simpler form from the usual integral expression form using suitable order parameters. The target coefficients A and B for the second order and fourth order terms, respectively, of the free energy are expressed as a function of temperature, film thickness, extrapolation length and other physical parameters. The intrinsic effects of surface on the order of phase transitions are discussed analytically with an emphasis on asymmetric films.
9 citations
TL;DR: The dielectric properties in 047Pb(Yb1/2Nb 1/2)O3-053PbTiO3 (047PYN−053PT) single crystals near the morphotropic phase boundary (MPB) were investigated in the frequency range from 10 kHz to 1 MHz as discussed by the authors.
Abstract: The dielectric properties in 047Pb(Yb1/2Nb1/2)O3–053PbTiO3 (047PYN–053PT) single crystals near the morphotropic phase boundary (MPB) were investigated in the frequency range from 10 kHz to 1 MHz Remarkable dielectric relaxation was observed along the polar 〈001〉 direction in the tetragonal 047PYN–053PT single crystal near the MPB An increase of the dielectric relaxation time was observed as the Curie temperature was approached The real part and the imaginary part of the complex relative permittivity obeys the Cole–Cole arc law, and the Debye type dielectric dispersion with the polydispersive type among the order-disorder type ferroelectrics was observed
9 citations
Journal Article•
4 citations
TL;DR: In this paper, the elastic stiffness constants in Martensite alloys with the symmetry change from the cubic m\bar3m to the tetragonal 4/mmm and the orthorhombic mmm symmetries were discus...
Abstract: Temperature dependence of the elastic stiffness constants in Martensite alloys with the symmetry change from the cubic m\bar3m to the tetragonal 4/mmm and the orthorhombic mmm symmetries was discus...
4 citations
TL;DR: In this article, the phase diagram and elastic stiffness constants in Martensite alloys with the symmetry change from the cubic m\bar3m to the tetragonal 4/mmm and the orthorhombic mmm symmetries are discussed on the basis of the Landau-type free energy function expressed in terms of the strain components, u 1, u 2 and u 3.
Abstract: The phase diagram and elastic stiffness constants in Martensite alloys with the symmetry change from the cubic m\bar3m to the tetragonal 4/mmm and the orthorhombic mmm symmetries are discussed on the basis of the Landau-type free energy function expressed in terms of the strain components, u 1 , u 2 and u 3 . It was found that some of elastic stiffness constants corresponding to the shear deformation become extremely small not only in the vicinity of the transition temperature but also near the morphotropic phase boundary where the Landau-type free energy function is isotropic or less anisotropic in the order parameter space.
4 citations
Journal Article•
Journal Article•
TL;DR: In this article, a single crystal near a morphotropic phase boundary (MPB) exhibits complex domain structures, which consist of both the rhombohedral and the tetragonal phase intimately mixed together.
Abstract: Domain structrues in 0.72Pb(In1/2Nb1/2)O3-0.28PbTiO3[0.72PIN-0.28PT]mixed crystal was investigated by a polarized light microscopy. It was found that the (001) plate of 0.72PIN-0.28PT single crystal near a morphotropic phase boundary (MPB) exhibits complex domain structures, which consist of both the rhombohedral and the tetragonal phase intimately mixed together. The change in domain structures, reflecting the successive rhombohedral-tetragonal-cubic phase transition with heating was observed. The temperature dependence of the birefringence in 0.72PIN-0.28PT single crystal near a MPB was also presented. The change in domain structures in the (001) plate of 0.72PIN-0.28PT with the phase transition from rhombohedral to tetragonal induced by applying the dc bias field along the direction at about 17 kV/cm was observed.
01 Jan 2003
TL;DR: In this article, the authors studied the traffic flow in the extended Burgers cellular automaton (EBCA1) traffic model and found three kinds of metastable local congested states in a two-dimensional region on the density-flow diagram.
Abstract: Traffic flow in the extended Burgers cellular automaton (EBCA1) traffic model is studied. The flow and configuration of vehicles on two lanes in the model are simulated and three kinds of metastable local congested states are found in a two-dimensional region on the density-flow diagram. The first is that cars advance by stop and go-flow on their own lanes without lane-change and values of the flow are stable in time. The second is that cars change the lane periodically with several time-steps. The third is that they advance changing the lane that induces fluctuation of the flow with extremely long period. This fluctuation flow exists in a wide range between car densities 5/12 and 3/4. The metastable flow is discussed in connection with the synchronized states observed in the traffic flow on an expressway.
Journal Article•
TL;DR: In this article, a review of generalized continuum theories applied to the crystals with complicated microscopic structure is given, where three different ways of generalization of the classical elasticity theory are discussed.
Abstract: We give a brief review of some generalized continuum theories applied to the crystals with complicated microscopic structure. Three different ways of generalization of the classical elasticity theory are discussed. One is the high-gradient theory, another is the micropolar type theory and the third one is the many-field theory. The importance of the first two types of theories has already been established, while the theory of the third type still has to be developed. With the use of 1D and 2D examples we show for each of these theories where they can be and should be applied, separately or in a combination.