Analysis and Design of Smart Electromagnetic Structures

2008 ◽  
Author(s):  
Prashanth Ramesh ◽  
Gregory Washington
Keyword(s):  
Dielectric Permittivity ◽  
Electric Field ◽  
Ambient Temperature ◽  
Ferroelectric Properties ◽  
Mechanical Strain ◽  
Ferroelectric Materials ◽  
Analysis And Design ◽  
Antenna Performance ◽  
Active Research ◽  
The Relationship

Use of ferroelectric materials to improve antenna performance is an area of active research. Applying an electric field across a ferroelectric used as the dielectric in an antenna enables tuning the antenna performance. Ferroelectrics also have coupled electromechanical behavior due to which it is sensitive to mechanical strains and fluctuations in ambient temperature. Use of ferroelectrics in antenna structures, especially those subject to mechanical and thermal loads, requires knowledge of the phenomenological relationship between the ferroelectric properties of interest (especially dielectric permittivity) and the external physical variables, viz. electric field(s), mechanical strains and temperature. To this end, a phenomenological model of ferroelectric materials based on the Devonshire thermodynamic theory is presented. This model is then used to obtain a relationship expressing the dependence of the dielectric permittivity on the mechanical strain, applied electric field and ambient temperature. The relationship is compared with published experimental data and other models in literature. Subsequently, a relationship expressing the dependence of antenna performance on those physical quantities is described.

scholarly journals Probing the Giant Piezoelectric response of ferroelectric perovskites

2014 ◽  
Vol 70 (a1) ◽  
pp. C150-C150
Author(s):  
Jerome Rouquette ◽  
Manuel Hinterstein ◽  
Julien Haines ◽  
Michael Knapp ◽  
Julia Glaum ◽  
...  
Keyword(s):  
Electric Field ◽  
Ferroelectric Properties ◽  
Structural Phase ◽  
Mechanical Strain ◽  
Domain Wall Motion ◽  
Ferroelectric Materials ◽  
Atomic Scale ◽  
Piezoelectric Response ◽  
Perovskite Materials

By analogy with ferromagnetism and the hysteresis of the magnetic moment with a magnetic field, materials that exhibit a macroscopic spontaneous polarization Ps, which can be reversed under electric field E were defined as ferroelectrics. Ps, the directional order parameter can give rise to different polar structural phase transitions and finally disappear as a function of temperature T and/or hydrostatic pressure P in a transformation from a non-centrosymmetric to a centrosymmetric space group. The physical properties of ferroelectric materials are the basis of many technological applications based on their hysteretic properties (Ps / E in ferroelectric random access memories) or based on their coupled properties (η (mechanical strain)/ E in piezoelectric applications). In order to understand the origin and the mechanisms associated with the ferroelectric properties, "in-situ" structural studies as a function of E, T and P have to be performed. In addition ferroelectric materials exhibit based on their directional properties (Ps) a particular domain configuration which makes the structural understanding of these compounds much more complex. Different scales should be taken into account: from the atomic scale (individual polar displacements) to the macroscopic scale (macroscopic piezoelectric effect) and finally the mesoscopic scale in between, which is governed by the domain wall motion. High piezoelectric/ferroelectric properties in lead perovskite materials (PZT, PMN, PZN) are structurally linked to strong disorder which can be characterized by the presence of diffuse scattering in diffraction experiments and by nanosized domains. Here we will present "in-situ" characterization in lead perovskite materials as a function of the applied electric field based on X-ray and neutron diffraction and EXAFS techniques. A brief overview of the challenges to solve in future studies as a function of pressure and temperature will also be discussed.

scholarly journals Influence of Applied Stress on the Ferroelectricity of Thin Zr-Doped HfO2 Films

2021 ◽  
Vol 11 (9) ◽  
pp. 4295
Author(s):  
Yuwei Cai ◽  
Qingzhu Zhang ◽  
Zhaohao Zhang ◽  
Gaobo Xu ◽  
Zhenhua Wu ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Integrated Circuit ◽  
Annealing Temperature ◽  
Ferroelectric Properties ◽  
Great Influence ◽  
Ferroelectric Material ◽  
Ferroelectric Materials ◽  
Fatigue Properties ◽  
The Relationship ◽  
Circuit Technology

HfO2-based ferroelectric materials have been widely studied for their application in ferroelectric FETs, which are compatible with conventional CMOS processes; however, problems with the material’s inherent fatigue properties have limited its potential for device application. This paper systematically investigates the effects of tensile stress and annealing temperature on the endurance and ferroelectric properties faced by Zr-doped HfO2 ferroelectric film. The remnant polarization (Pr) shows an increasing trend with annealing temperature, while the change in the coercive electric field (Ec) is not obvious in terms of the relationship with tensile stress or annealing temperature. In addition, the application of tensile stress does help to improve the endurance characteristics by about two orders of magnitude for the ferroelectric material, and the endurance properties show a tendency to be negatively correlated with annealing temperature. Overall, although the effect of stress on the ferroelectricity of a HZO material is not obvious, it has a great influence on its endurance properties and can optimize the endurance of the material, and ferroelectricity exhibits a higher dependence on temperature. The optimization of the endurance properties of HZO materials by stress can facilitate their development and application in future integrated circuit technology.

THE EFFECT OF ELECTRIC FIELD ON THE DIELECTRIC PERMITTIVITY OF BST/STO SUPERLATTICE

2013 ◽  
Vol 27 (10) ◽  
pp. 1350066 ◽  
Author(s):  
ZHI-GAO ZUO ◽  
FU-RI LING ◽  
DAN LI ◽  
JIN-SONG LIU ◽  
JIAN-QUAN YAO
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
External Electric Field ◽  
Ferroelectric Properties ◽  
Transformation Strain ◽  
Elastic Interaction ◽  
Dielectric Behavior ◽  
Electrical Field ◽  
External Electrical Field

A nonlinear thermodynamic model is developed for investigating the effect of external electric field on the dielectric properties of Ba 0.6 Sr 0.4 TiO 3/ SrTiO 3( BST / STO ) super-lattice. The transformation strain induced by the external electrical field are analyzed and calculated. It is found that the dielectric and ferroelectric properties of the ( BST / STO ) superlattice vary substantially with the interlayer elastic interaction caused by the external electrical field. The results also provide better understanding of the dielectric behavior of BST / STO superlattice with external electric field and a necessary step in the development of the general nonlinear theory.

The combined effect of mechanical strain and electric field cycling on the ferroelectric performance of P(VDF-TrFE) thin films on flexible substrates and underlying mechanisms

2016 ◽  
Vol 18 (42) ◽  
pp. 29478-29485 ◽  
Author(s):  
Deepa Singh ◽  
Deepak Deepak ◽  
Ashish Garg
Keyword(s):  
Thin Film ◽  
Electric Field ◽  
Ferroelectric Properties ◽  
Mechanical Strain ◽  
Combined Effect ◽  
Flexible Substrates ◽  
Thin Film Capacitors ◽  
Field Cycling ◽  
Underlying Mechanisms ◽  
Memory Applications

In this manuscript, we study the combined effect of mechanical strain and electric field cycling on the ferroelectric properties and polarization fatigue of P(VDF-TrFE) based flexible thin film capacitors from the perspective of flexible memory applications.

Modification of Ferroelectric Properties of TGS Crystals Grown under a dc Electric field

2000 ◽  
Vol 658 ◽  
Author(s):  
G. Arunmozhi ◽  
E. Nogueira ◽  
E.de Matos Gomes ◽  
S. Lanceros-Mendez ◽  
M. Margarida ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Electric Field ◽  
Ferroelectric Phase ◽  
Ferroelectric Properties ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Triglycine Sulphate ◽  
X Ray ◽  
Dc Electric Field ◽  
Diffraction Patterns

ABSTRACTFerroelectric triglycine sulphate crystals have been grown under the influence of an intense electric field of 6×104 V/m. Relative to crystals grown under ambient conditions (TGS) the crystals grown under the electric field (TGS-E) display a dielectric permittivity a factor of two lower. Significant differences are observed in the Curie-Weiss behavior of the ferroelectric phase, in the x-ray diffraction patterns and in the differential calorimetry measurements.

scholarly journals THE CONTRIBUTION OF ELECTRICAL CONDUCTIVITY, DIELECTRIC PERMITTIVITY AND DOMAIN SWITCHING IN FERROELECTRIC HYSTERESIS LOOPS

2011 ◽  
Vol 01 (01) ◽  
pp. 107-118 ◽  
Author(s):  
HAIXUE YAN ◽  
FAWAD INAM ◽  
GIUSEPPE VIOLA ◽  
HUANPO NING ◽  
HONGTAO ZHANG ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Domain Switching ◽  
Ferroelectric Properties ◽  
Electric Displacement ◽  
Hysteresis Loops ◽  
Lead Zirconate ◽  
Ferroelectric Hysteresis ◽  
Current Electric Field

Triangular voltage waveform was employed to distinguish the contributions of dielectric permittivity, electric conductivity and domain switching in current-electric field curves. At the same time, it is shown how those contributions can affect the shape of the electric displacement — electric field loops (D–E loops). The effects of frequency, temperature and microstructure (point defects, grain size and texture) on the ferroelectric properties of several ferroelectric compositions is reported, including: BaTiO 3; lead zirconate titanate (PZT); lead-free Na 0.5 K 0.5 NbO 3; perovskite-like layer structured A 2 B 2 O 7 with super high Curie point (T c ); Aurivillius phase ferroelectric Bi 3.15 Nd 0.5 Ti 3 O 12; and multiferroic Bi 0.89 La 0.05 Tb 0.06 FeO 3. This systematic study provides an instructive outline in the measurement of ferroelectric properties and the analysis and interpretation of experimental data.

Analysis of Retention Time Degradation Caused by Electrostatic Potential Variation between Adjacent Bit-Line and Adjacent Contact Node in DRAM

2016 ◽  
Author(s):  
Jungil Mok ◽  
Byungki Kang ◽  
Daesun Kim ◽  
Hongsun Hwang ◽  
Sangjae Rhee ◽  
...  
Keyword(s):  
Electric Field ◽  
Electrostatic Potential ◽  
Critical Dimension ◽  
Data Retention ◽  
Signal Line ◽  
Adjacent Node ◽  
Storage Node ◽  
Retention Characteristics ◽  
Node Voltage ◽  
The Relationship

Abstract Systematic retention failure related on the adjacent electrostatic potential is studied with sub 20nm DRAM. Unlike traditional retention failures which are caused by gate induced drain leakage or junction leakage, this failure is influenced by the combination of adjacent signal line and adjacent contact node voltage. As the critical dimension between adjacent active and the adjacent signal line and contact node is scaled down, the effect of electric field caused by adjacent node on storage node is increased gradually. In this paper, we will show that the relationship between the combination electric field of adjacent nodes and the data retention characteristics and we will demonstrate the mechanism based on the electrical analysis and 3D TCAD simulation simultaneously.

scholarly journals Changes in ambient temperature increase hospital outpatient visits for allergic rhinitis in Xinxiang, China

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Jianhui Gao ◽  
Mengxue Lu ◽  
Yinzhen Sun ◽  
Jingyao Wang ◽  
Zhen An ◽  
...  
Keyword(s):  
Allergic Rhinitis ◽  
Ambient Temperature ◽  
Positive Association ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Hospital Outpatient ◽  
Distributed Lag ◽  
Outpatient Visits ◽  
Daily Data ◽  
The Relationship

Abstract Background The effect of ambient temperature on allergic rhinitis (AR) remains unclear. Accordingly, this study aimed to explore the relationship between ambient temperature and the risk of AR outpatients in Xinxiang, China. Method Daily data of outpatients for AR, meteorological conditions, and ambient air pollution in Xinxiang, China were collected from 2015 to 2018. The lag-exposure-response relationship between daily mean temperature and the number of hospital outpatient visits for AR was analyzed by distributed lag non-linear model (DLNM). Humidity, long-time trends, day of the week, public holidays, and air pollutants including sulfur dioxide (SO2), and nitrogen dioxide (NO2) were controlled as covariates simultaneously. Results A total of 14,965 AR outpatient records were collected. The relationship between ambient temperature and AR outpatients was generally M-shaped. There was a higher risk of AR outpatient when the temperature was 1.6–9.3 °C, at a lag of 0–7 days. Additionally, the positive association became significant when the temperature rose to 23.5–28.5 °C, at lag 0–3 days. The effects were strongest at the 25th (7 °C) percentile, at lag of 0–7 days (RR: 1.32, 95% confidence intervals (CI): 1.05–1.67), and at the 75th (25 °C) percentile at a lag of 0–3 days (RR: 1.15, 95% CI: 1.02–1.29), respectively. Furthermore, men were more sensitive to temperature changes than women, and the younger groups appeared to be more influenced. Conclusions Both mild cold and mild hot temperatures may significantly increase the risk of AR outpatients in Xinxiang, China. These findings could have important public health implications for the occurrence and prevention of AR.

Fabrication of V-Substituted (Bi,M)4Ti3O12 [M = Lanthanoids] Thin Films by Chemical Solution Deposition Method

2001 ◽  
Vol 688 ◽  
Author(s):  
H. Uchida ◽  
H. Yoshikawa ◽  
I. Okada ◽  
H. Matsuda ◽  
T. Iijima ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Solution Deposition ◽  
Bismuth Titanate ◽  
Ferroelectric Properties ◽  
Ferroelectric Materials ◽  
Processing Temperature ◽  
Chemical Solution ◽  
Si Substrate ◽  
Solution Deposition ◽  
Chemical Solution Deposition Method

AbstractBismuth titanate (Bi4Ti3O12; BIT) -based ferroelectric materials are proposed from the view of the “Site-engineering”, where the Bi-site ions are substituted by lanthanoid ions (La3+ and Nd3+) and Ti-site ions by other ions with higher charge valence (V5+). In the present study, influences of vanadium (V) - substitution for (Bi,M)4Ti3O12 thin films [M = lanthanoid] on the ferroelectric properties are evaluated. V-substituted (Bi,M)4Ti3O12 films have been fabricated using a chemical solution deposition (CSD) technique on the (111)Pt/Ti/SiO2/(100)Si substrate. Remnant polarization of (Bi,La)4Ti3O12 and (Bi,Nd)4Ti3O12 films has been improved by the V-substitution independent of the coercive field. The processing temperature of BLT and BNT films could also be lowered by the V-substitution.

Experimental Research of Energy Harvesting and Storage Based on Ferroelectric Materials

2012 ◽  
Vol 476-478 ◽  
pp. 1336-1340
Author(s):  
Kai Feng Li ◽  
Rong Liu ◽  
Lin Xiang Wang
Keyword(s):  
Energy Harvesting ◽  
Electromagnetic Waves ◽  
Vibrational Energy ◽  
Waste Heat ◽  
Mechanical Strain ◽  
Electrical Potential ◽  
Electrical Energy ◽  
Ferroelectric Materials ◽  
Energy Scavenging ◽  
And Storage

The concept of energy harvesting works towards developing self-powered devices that do not require replaceable power supplies. Energy scavenging devices are designed to capture the ambient energy surrounding the electronics and convert it into usable electrical energy. A number of sources of harvestable ambient energy exist, including waste heat, vibration, electromagnetic waves, wind, flowing water, and solar energy. While each of these sources of energy can be effectively used to power remote sensors, the structural and biological communities have placed an emphasis on scavenging vibrational energy with ferroelectric materials. Ferroelectric materials have a crystalline structure that provide a unique ability to convert an applied electrical potential into a mechanical strain or vice versa. Based on the properties of the material, this paper investigates the technique of power harvesting and storage.

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