Showing papers on "Ferroelasticity published in 2008"
TL;DR: In this paper, the symmetry conditions for the occurrence in a same phase of one or more of the four primary ferroic properties, i.e., ferroelectricity, ferromagnetism, ferrotoroidicity and ferroelasticity, are discussed.
Abstract: The symmetry conditions for the occurrence in a same phase of one or more of the four primary ferroic properties, i.e., ferroelectricity, ferromagnetism, ferrotoroidicity and ferroelasticity, are discussed. Analogous conditions are outlined for the admission of so-called secondary and tertiary ferroic effects, such as magnetoelectric, piezoelectric, piezomagnetic, piezotoroidic, etc. Formerly postulated 'magnetotoroidic' and 'electrotoroidic' effects are found to be describable as tertiary ferroic magnetoelectric effects. For understanding ferroic and multiferroic domains and their possibilities of switching, knowledge of the pairs of prototype point group/ferroic phase point group (so-called 'Aizu species') is decisive. A classification into ensembles of species with common properties, recently extended to ferrotoroidic crystals, allows distinguishing between full, partial or no coupling between order parameters and understanding domain patterns and poling procedures. The switching by reorientation with angles other than 180° of ferromagnetic, antiferromagnetic and ferroelectric domains by magnetic fields, electric fields or by stress requires the ferroic phase to be ferroelastic. For ferromagnetic/ferrotoroidic and antiferromagnetic/ferrotoroidic phases, the ferrotoroidic domains are found to be identical with the ferromagnetic and antiferromagnetic ones, respectively. As a consequence and depending on symmetry, ferrotoroidic domains can be switched by crossed electric and magnetic fields, by collinear electric and magnetic fields or by a magnetic field alone. Examples of ferrotoroidic domains are discussed for Fe2−xGaxO3,Co3B7O13Br and LiCoPO4. Recent new results on symmetry and domains of the antiferromagnetic incommensurate phase of BiFeO3 are also discussed.
328 citations
TL;DR: In this paper, single crystals of multiferroic BiFeO3 were investigated using neutron scattering, and the application of an electric field reversibly switches ferroelastic domains, inducing changes in the magnetic structure which follows rotation of the structural domains.
Abstract: Single crystals of multiferroic BiFeO3 were investigated using neutron scattering. Application of an electric field reversibly switches ferroelastic domains, inducing changes in the magnetic structure which follows rotation of the structural domains. In addition, electric fields can be used to control the populations of the equivalent magnetic domains within a single ferroelastic domain, possibly via field-induced strain.
110 citations
TL;DR: The solid solubility between LaNbO4 and LaTaO4 was investigated by X-ray diffraction, and a two-phase region was observed in the composition region La Nb1−xTaxO4 where 0.4⩽x-0.8 was shown to increase with increasing Ta-content as discussed by the authors.
72 citations
TL;DR: In this article, local polarization switching in epitaxial ferroelectric thin films in the presence of ferroelastic domain walls was studied using phase-field approach and the nucleation bias profile across a twin wall was analyzed, and the localization of preferential nucleation sites was established.
Abstract: Local polarization switching in epitaxial ferroelectric thin films in the presence of ferroelastic domain walls was studied using phase-field approach The nucleation bias profile across a twin wall was analyzed, and the localization of preferential nucleation sites was established This analysis was further extended to a realistic domain structure with multiple twin boundaries It was observed that the local nucleation voltage required for a 180° domain switching is closely related to the number of such local defects
36 citations
TL;DR: In this paper, the authors reported the observation of a weak ferromagnetic transition at TN=122K in a K3Fe5F15 system which is ferroelectric and ferroelastic below Tc=490K.
Abstract: Here, we report on the observation of a weak ferromagnetic transition at TN=122K in a K3Fe5F15 system which is ferroelectric and ferroelastic below Tc=490K The magnetization and the susceptibility continuously increase with decreasing T down to 2K The Mossbauer spectra show a spontaneous magnetic ordering and at least three sites corresponding to Fe2+ and Fe3+ The ratio between Fe2+ and Fe3+ is 60:40 At 6K, there are two magnetically ordered sextets with internal fields of 585 and 263kOe The “slim” hysteresis loops observed are as well characteristic of weak ferromagnetism At 122K and at low frequencies, the system shows dielectric anomaly characteristic of magnetoelectric behavior
26 citations
TL;DR: A study of the domain configuration in the 0.5BiFeO3-0.5PbTiO3 composition using electron backscatter diffraction to demonstrate the ability of the technique to map ferroelastic domain structures at the micron and submicron scale.
Abstract: xBiFeO3-(1-x)PbTiO3 single crystals were grown via a flux method for a range of compositions. Presented here is a study of the domain configuration in the 0.5BiFeO3-0.5PbTiO3 composition using electron backscatter diffraction to demonstrate the ability of the technique to map ferroelastic domain structures at the micron and submicron scale. The micron-scale domains exhibit an angle of approximately 85deg between each variant, indicative of a ferroelastic domain wall in a tetragonal system with a spontaneous strain, c/a - 1 of 0.10, in excellent agreement with the lattice parameters derived from X-ray diffraction. Contrast seen in forescatter images is attributed to variations in the direction of the electrical polarization vector, providing images of ferroelectric domain patterns.
14 citations
TL;DR: In this paper, the authors investigate theoretically ferroelastic domain fraction in a heteroepitaxial bilayer consisting of (1) tetragonal PbZrxTi1−xO3 and (2) rhombohedral pbZr 1−xTixO3 on a thin substrate as a function of the lattice misfit strain between layers and the substrate.
Abstract: We investigate theoretically ferroelastic domain fractions in a heteroepitaxial bilayer consisting of (001) tetragonal PbZrxTi1−xO3 and (001) rhombohedral PbZr1−xTixO3 on a thick (001) passive substrate as a function of the lattice misfit strain between layers and the substrate. By considering the self-strain in each layer and the indirect elastic interaction between the layers, we provide a numerical analysis of the relative domain fractions in the tetragonal layer of a (001)PbZr0.2Ti0.8O3/(001)PbZr0.8Ti0.2O3 and (001)PbZr0.4Ti0.6O3/(001)PbZr0.6Ti0.4O3 bilayer structure as a function of the tetragonal layer thickness on (001)LaAlO3, (001)SrTiO3, and (001) MgO. It is found that the elastic coupling between the tetragonal and rhombohedral layers leads to an excess elastic energy in the tetragonal layer, resulting in a two to three times increase in the ferroelastic domain volume fraction of the tetragonal layer compared to single-layer films of similar thickness. These results show alternate ways of engine...
14 citations
TL;DR: In this article, a radial mechanical compressive stress is applied transverse to the electric field, increasing the potential for domain alignment during poling by taking advantage of ferroelasticity.
Abstract: In many polycrystalline piezoelectric ceramics, domain switching during the poling process leads to the development of a macroscopic polarization and piezoelectric behavior. Traditionally, poling involves the application of electric fields across two parallel electrodes. In the present work, a radial mechanical compressive stress is applied transverse to the electric field, increasing the potential for domain alignment during poling by taking advantage of ferroelasticity. Experiments demonstrate that poling of lead zirconate titanate using a combination of an electric field and a transverse mechanical compressive stress increases the d33 coefficient from 435 to 489 pC/N. Using neutron diffraction and pole figure inversion methods, the degree of non-180° domain switching is described using pole density distributions of the tetragonal c-axis (002). The degree of 002 domain alignment parallel to the electric field after the electromechanical poling process increases from 1.30 multiples of a random distribution (mrd) to >1.40 mrd at stresses exceeding 40 MPa.
13 citations
TL;DR: In this article, the authors deal with ferroelastic domain switching around a stationary crack tip in a single crystal for potential applications in the context of crack toughening, and the main focus is directed towards the effect of transformation stresses on the domain.
7 citations
TL;DR: In this paper, the temperature evolution of the lattice parameters measured from 295 to 125 K exhibits a small instability below Tc≈278 K, indicating ferroelastic properties of Na2TiGeO5, which is related to the specific crystal structure built of polyhedral layers with shared TiO5 pyramids and GeO4 tetrahedra.
5 citations
TL;DR: In this paper, the polarization switching process in ferroelastic-ferroelectric ceramics through hysteresis loops and the electric field induced-strain measurements was investigated.
Abstract: The polarization switching process was investigated in ferroelastic-ferroelectric ceramics through hysteresis loops and the electric field induced-strain measurements. PMN-PT ceramics with rhombohedral and tetragonal symmetries as well as soft and hard PZT ceramics were investigated. The ferroelectric polarization switching in ceramics was emphasized as an elastic problem related to ferroelastic non-180° domains. The domain reorientation was showed as occurring in a viscous medium, where the “active” domains lie in a conical distribution and the restoring forces are resulting from electrical and mechanical contributions. The coercive field was interpreted as the effective field necessary to overcome these resistance forces during the reorientation process.
TL;DR: In this paper, the authors reviewed the results of their studies concerning the ferroelastic domain structure in the crystals exhibiting superprotonic conductivity, and they showed the temperature evolution of ferro-elastic pattern at ferro/paraelastic-super protonic phase transitions as well as at other structural phase transitions.
Abstract: The paper reviews the results of our studies concerning the ferroelastic domain structure in the crystals exhibiting superprotonic conductivity. We would like to show the ferroelastic domain structure and its temperature behaviour in solid acids which belong to the family of crystals with a general formula M x Li y H z (XO 4 )(x + y + z)/2 (M = Rb,K,Cs,NH 4 ; X = S and Se). For the majority of crystals, which belong to that family, the transition to the phase with high proton conductivity is simultaneously the ferroelastic-paraelastic one. However, this does not apply to all crystals of the family. Therefore, a question arises about the role of the phenomenon of ferroelasticity in the superprotonic phase transition. Depending on x,y and z, there are different groups of crystals. Our paper presents the results of temperature evolution of ferroelastic domain pattern at ferroelastic-superprotonic phase transitions as well as at other structural phase transitions, which appear in different crystal groups.
TL;DR: In this paper, the authors carried out the electrical conductivity measurement under the uniaxial stress in the hydrogen-bonded superprotonic conductor Cs3H(SeO4)2.
TL;DR: In this paper, phase transition studies of sodium doped Lithium potassium sulphate, Li K 0.9 Na 0.1 SO 4, crystal by ultrasonic Pulse Echo Overlap [PEO] technique are reported for the first time.
Abstract: Phase transition studies of sodium doped Lithium potassium sulphate, Li K 0.9 Na 0.1 SO 4 , crystal by ultrasonic Pulse Echo Overlap [PEO] technique are reported for the first time. The crystal shows pyroelectric, ferroelectric and electro optic properties. It is simultaneously ferroelastic and superionic. This study reported elastic properties and checked the effect of doping on suspected phase transition around 333 K as reported by Brillouin and thermal expansion studies. The transverse modes C 44 and C 66 show elastic anomalies around 333 K.
01 Jan 2008
TL;DR: Orientation of compatible domain walls, magnitude of disorientation angles and shear angle of ferroelastic domain twins resulting from the hexagonal-orthorhombic phase transitions are discussed in this paper.
Abstract: Orientation of compatible domain walls, magnitude of disorientation angles and shear angle of ferroelastic domain twins resulting from the hexagonal–orthorhombic phase transitions are discussed. Magnitude of shear angle is expressed using crystallographic unit-cell parameters of the low-symmetry phase.