Investigations on Multi-axial Domain Switching Criteria for Piezoceramics

2005 ◽  
Vol 881 ◽  
Author(s):  
Bernd Laskewitz ◽  
Dayu Zhou ◽  
Marc Kamlah
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Domain Switching ◽  
Axial Stress ◽  
Initial Domain ◽  
Hollow Cylinders ◽  
Thin Walled ◽  
Electromechanical Loading ◽  
Stress States ◽  
Strain Responses

AbstractInitially unpoled soft PZT was subjected to a proportional, coaxial electromechanical loading. The ratio of compressive stress to electric field was changed between the experiments. From this series of nonlinear polarization and strain responses were obtained. Based on an offset method, initial domain switching states in the two-dimensional stress-electric field space were determined. In continuum mechanics, thin walled tubes are used to investigate multi-axial stress states. In this context, thin walled means a ratio of wall thickness to radius of 1:10 or thinner. However, simple linear dielectric analysis indicates an inhomogeneous electric field distribution in such geometries.Therefore, the suitability of hollow cylinders (in the range from thick to thin walled tubes) for multi-axial electromechanical experiments has to be investigated. Simulations with a finite element tool based on a phenomenological constitutive model for ferroelectric and ferroelastic hysteresis behavior were performed. The results confirm inhomogeneous distributions of electric fields and stresses after poling. A geometry variation is discussed to minimize these effects.

Crack tip 90° domain switching in tetragonal lanthanum-modified lead zirconate titanate under an electric field

1999 ◽  
Vol 14 (7) ◽  
pp. 2940-2944 ◽  
Author(s):  
Fei Fang ◽  
Wei Yang ◽  
Ting Zhu
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Lead Zirconate Titanate ◽  
Powder Processing ◽  
Domain Switching ◽  
Crack Tip ◽  
Lead Zirconate ◽  
Processing Technique ◽  
Ferroelectric Ceramics ◽  
Zirconate Titanate

Lanthanum-modified lead zirconate titanate ferroelectric ceramics (Pb0.96La0.04)(Zr0.40Ti0.60)0.99O3 were synthesized by the conventional powder processing technique. X-ray diffraction experiments revealed that the samples belong to the tetragonal phase with a = b = 0.4055 nm, c = 0.4109 nm, and c/a = 1.013. After being poled, the samples were indented with a 5-kg Vickers indenter, and lateral electric fields of 0.4 Ec, 0.5 Ec, and 0.6 Ec (Ec = 1100 V/mm) were applied, respectively. Field-emission scanning electron microscopy showed that 90° domain switching appeared near the tip of the indentation crack under a lateral electric field of 0.6 Ec. A mechanism of 90° domain switching near the crack tip under an electric field is discussed.

Effect of Electromechanical Loadings on Fracture Strength of Piezoelectric Ceramics

2007 ◽  
Vol 353-358 ◽  
pp. 1544-1547
Author(s):  
Byeung Gun Nam ◽  
H.S. Na ◽  
R. Liu ◽  
Katsuhiko Watanabe
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Fracture Strength ◽  
Applied Electric Field ◽  
Crack Extension ◽  
Piezoelectric Ceramics ◽  
Fracture Load ◽  
Open Circuit ◽  
Condition Effect ◽  
Electromechanical Loading

The effect of electromechanical loadings including their sequence, which was motivated by the property of crack energy density for piezoelectric material, was experimentally investigated. Three-point bending fracture test was performed for two piezoelectric ceramics under different electromechanical loading conditions. It was found that the fracture loads under closed circuit condition are greater than those under open circuit condition. Effect of applied electric field on fracture load in the test varied with materials. Applied electric field always enhanced crack extension in C-21 ceramics regardless of their directions, while it produced very little effect on crack extension under negative electric fields in C-2 ceramics. It was also found that electromechanical loading sequence clearly affects fracture strength, although its effect varies also with materials.

Electric-Field-Control of Non-Volatile Magnetization Switching in Multiferroic CoFeB/(011)-PMN-PT Heterostructures

2016 ◽  
Vol 848 ◽  
pp. 675-681 ◽  
Author(s):  
Yuan Jun Yang ◽  
Bin Hong ◽  
Meng Meng Yang ◽  
Liang Xin Wang ◽  
Hao He ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Electric Field ◽  
Electric Fields ◽  
Room Temperature ◽  
Domain Switching ◽  
Magnetization Switching ◽  
Ultra Low Power ◽  
Spintronic Devices ◽  
Magnetic States ◽  
Pulse Electric

The giant converse magnetoelectric coupling (GME) was observed in the multiferroic Co40Fe40B20/(011)-0.7Pb (Mg1/3Nb2/3)O3-0.3PbTiO3 heterostructures at room temperature in this investigation. A tunability of magnetization by electric field along the [100] direction was up to-66.7% at-10 Oe bias magnetic fields. Moreover, the non-volatile magnetization switching was found after removal of bipolar electric field. The corresponding remanent magnetic states even without the assistance of bias magnetic fields were stable and could be modulated synchronously by a sequence of pulse electric fields. The 90o rotation of easy axis and non-symmetrical ferroelastic domain switching contributed to the above results. This work is of great significance in designing ultra-low power and non-volatile magnetoelectric memories and other spintronic devices at room temperature.

Influence of Electric Fields on the Fracture Behavior of Ferroelectric Ceramics under Combined Electromechanical Loading

2006 ◽  
Vol 306-308 ◽  
pp. 1199-1204 ◽  
Author(s):  
Zhan Wei Liu ◽  
Dai Ning Fang ◽  
Hui Min Xie
Keyword(s):  
Fracture Toughness ◽  
Electric Field ◽  
Electric Fields ◽  
Crack Extension ◽  
Fracture Behavior ◽  
Ferroelectric Ceramics ◽  
Normal Strain ◽  
Electric Field Direction ◽  
Poling Direction ◽  
Electromechanical Loading

In this paper, fracture behavior of ferroelectric ceramics under combined electromechanical loading was investigated using moiré interferometry. It is found that the influence of electric field on fracture toughness is not very larger in the case that the directions of the poling, electric field and crack extension are perpendicular to each other. When the poling direction is parallel to the crack extension direction and both are perpendicular to the electric field direction, the normal strain measured reduced faster than that calculated by FEM with and without electrical loading as the distance away from the crack tip increases. Fracture toughness decreases obviously as the electric-field intensity increases.

Tuning the Electric Field Response of MOFs by Rotatable Dipolar Linkers

2019 ◽  
Author(s):  
Johannes P. Dürholt ◽  
Babak Farhadi Jahromi ◽  
Rochus Schmid
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Structural Changes ◽  
Dielectric Behavior ◽  
Two Dimensions ◽  
Dielectric Constants ◽  
Electric Response ◽  
Dipole Strength ◽  
Metal Organic ◽  
Dynamics Simulations

Recently the possibility of using electric fields as a further stimulus to trigger structural changes in metal-organic frameworks (MOFs) has been investigated. In general, rotatable groups or other types of mechanical motion can be driven by electric fields. In this study we demonstrate how the electric response of MOFs can be tuned by adding rotatable dipolar linkers, generating a material that exhibits paralectric behavior in two dimensions and dielectric behavior in one dimension. The suitability of four different methods to compute the relative permittivity κ by means of molecular dynamics simulations was validated. The dependency of the permittivity on temperature T and dipole strength μ was determined. It was found that the herein investigated systems exhibit a high degree of tunability and substantially larger dielectric constants as expected for MOFs in general. The temperature dependency of κ obeys the Curie-Weiss law. In addition, the influence of dipolar linkers on the electric field induced breathing behavior was investigated. With increasing dipole moment, lower field strength are required to trigger the contraction. These investigations set the stage for an application of such systems as dielectric sensors, order-disorder ferroelectrics or any scenario where movable dipolar fragments respond to external electric fields.

scholarly journals Meta-Deflectors Made of Dielectric Nanohole Arrays with Anti-Damage Potential

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 107
Author(s):  
Haichao Yu ◽  
Feng Tang ◽  
Jingjun Wu ◽  
Zao Yi ◽  
Xin Ye ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Laser Cutting ◽  
High Complexity ◽  
Damage Potential ◽  
Optical Components ◽  
Nanohole Arrays ◽  
Intense Light ◽  
Polarization Of Light ◽  
Air Hole

In intense-light systems, the traditional discrete optical components lead to high complexity and high cost. Metasurfaces, which have received increasing attention due to the ability to locally manipulate the amplitude, phase, and polarization of light, are promising for addressing this issue. In the study, a metasurface-based reflective deflector is investigated which is composed of silicon nanohole arrays that confine the strongest electric field in the air zone. Subsequently, the in-air electric field does not interact with the silicon material directly, attenuating the optothermal effect that causes laser damage. The highest reflectance of nanoholes can be above 99% while the strongest electric fields are tuned into the air zone. One presentative deflector is designed based on these nanoholes with in-air-hole field confinement and anti-damage potential. The 1st order of the meta-deflector has the highest reflectance of 55.74%, and the reflectance sum of all the orders of the meta-deflector is 92.38%. The optothermal simulations show that the meta-deflector can theoretically handle a maximum laser density of 0.24 W/µm2. The study provides an approach to improving the anti-damage property of the reflective phase-control metasurfaces for intense-light systems, which can be exploited in many applications, such as laser scalpels, laser cutting devices, etc.

scholarly journals Integrating flexible electronics for pulsed electric field delivery in a vascularized 3D glioblastoma model

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Marie C. Lefevre ◽  
Gerwin Dijk ◽  
Attila Kaszas ◽  
Martin Baca ◽  
David Moreau ◽  
...  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Flexible Electronics ◽  
Soft Tissues ◽  
Multiphoton Microscopy ◽  
Membrane Integrity ◽  
Tumor Model ◽  
Pulsed Electric Fields ◽  
In Ovo ◽  
Cell Membrane Integrity

AbstractGlioblastoma is a highly aggressive brain tumor, very invasive and thus difficult to eradicate with standard oncology therapies. Bioelectric treatments based on pulsed electric fields have proven to be a successful method to treat cancerous tissues. However, they rely on stiff electrodes, which cause acute and chronic injuries, especially in soft tissues like the brain. Here we demonstrate the feasibility of delivering pulsed electric fields with flexible electronics using an in ovo vascularized tumor model. We show with fluorescence widefield and multiphoton microscopy that pulsed electric fields induce vasoconstriction of blood vessels and evoke calcium signals in vascularized glioblastoma spheroids stably expressing a genetically encoded fluorescence reporter. Simulations of the electric field delivery are compared with the measured influence of electric field effects on cell membrane integrity in exposed tumor cells. Our results confirm the feasibility of flexible electronics as a means of delivering intense pulsed electric fields to tumors in an intravital 3D vascularized model of human glioblastoma.

scholarly journals Electro-Optic Control of Lithium Niobate Bulk Whispering Gallery Resonators: Analysis of the Distribution of Externally Applied Electric Fields

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 298
Author(s):  
Yannick Minet ◽  
Hans Zappe ◽  
Ingo Breunig ◽  
Karsten Buse
Keyword(s):  
Lithium Niobate ◽  
Electric Field ◽  
Electric Fields ◽  
Frequency Comb ◽  
Parametric Oscillation ◽  
Pockels Effect ◽  
Optical Mode ◽  
Cylindrical Resonator ◽  
Whispering Gallery ◽  
Electro Optic

Whispering gallery resonators made out of lithium niobate allow for optical parametric oscillation and frequency comb generation employing the outstanding second-order nonlinear-optical properties of this material. An important knob to tune and control these processes is, e.g., the linear electro-optic effect, the Pockels effect via externally applied electric fields. Due to the shape of the resonators a precise prediction of the electric field strength that affects the optical mode is non-trivial. Here, we study the average strength of the electric field in z-direction in the region of the optical mode for different configurations and geometries of lithium niobate whispering gallery resonators with the help of the finite element method. We find that in some configurations almost 100% is present in the cavity compared to the ideal case of a cylindrical resonator. Even in the case of a few-mode resonator with a very thin rim we find a strength of 90%. Our results give useful design considerations for future arrangements that may benefit from the strong electro-optic effect in bulk whispering gallery resonators made out of lithium niobate.

Determination of a Rubber-Like Material Model as an Inverse Problem

2011 ◽  
Vol 70 ◽  
pp. 225-230 ◽  
Author(s):  
Agnieszka Derewonko ◽  
Andrzej Kiczko
Keyword(s):  
Selection Process ◽  
Axial Stress ◽  
Constitutive Models ◽  
Material Model ◽  
Polyester Fabric ◽  
Point Of View ◽  
Air Cushion ◽  
Ill Conditioning ◽  
Stress States

The purpose of this paper is to describe the selection process of a rubber-like material model useful for simulation behaviour of an inflatable air cushion under multi-axial stress states. The air cushion is a part of a single segment of a pontoon bridge. The air cushion is constructed of a polyester fabric reinforced membrane such as Hypalon®. From a numerical point of view such a composite type poses a challenge since numerical ill-conditioning can occur due to stiffness differences between rubber and fabric. Due to the analysis of the large deformation dynamic response of the structure, the LS-Dyna code is used. Since LS-Dyna contains more than two-hundred constitutive models the inverse method is used to determine parameters characterizing the material on the base of results of the experimental test.

scholarly journals Double layers in the downward current region of the aurora

2003 ◽  
Vol 10 (1/2) ◽  
pp. 45-52 ◽  
Author(s):  
R. E. Ergun ◽  
L. Andersson ◽  
C. W. Carlson ◽  
D. L. Newman ◽  
M. V. Goldman
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Phase Space ◽  
Electric Field ◽  
Electric Fields ◽  
Double Layers ◽  
Parallel Electric Field ◽  
Electrostatic Waves ◽  
Current Region ◽  
Decisive Evidence

Abstract. Direct observations of magnetic-field-aligned (parallel) electric fields in the downward current region of the aurora provide decisive evidence of naturally occurring double layers. We report measurements of parallel electric fields, electron fluxes and ion fluxes related to double layers that are responsible for particle acceleration. The observations suggest that parallel electric fields organize into a structure of three distinct, narrowly-confined regions along the magnetic field (B). In the "ramp" region, the measured parallel electric field forms a nearly-monotonic potential ramp that is localized to ~ 10 Debye lengths along B. The ramp is moving parallel to B at the ion acoustic speed (vs) and in the same direction as the accelerated electrons. On the high-potential side of the ramp, in the "beam" region, an unstable electron beam is seen for roughly another 10 Debye lengths along B. The electron beam is rapidly stabilized by intense electrostatic waves and nonlinear structures interpreted as electron phase-space holes. The "wave" region is physically separated from the ramp by the beam region. Numerical simulations reproduce a similar ramp structure, beam region, electrostatic turbulence region and plasma characteristics as seen in the observations. These results suggest that large double layers can account for the parallel electric field in the downward current region and that intense electrostatic turbulence rapidly stabilizes the accelerated electron distributions. These results also demonstrate that parallel electric fields are directly associated with the generation of large-amplitude electron phase-space holes and plasma waves.

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