Download or read book Flexoelectricity of Barium Strontium Titanate and Its Applications written by Seol Ryung Kwon and published by . This book was released on 2014 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flexoelectricity in Ceramics and their Application written by Satyanarayan Patel and published by Elsevier. This book was released on 2023-08-29 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flexoelectricity is the ability of materials to generate a voltage when they are bent or, conversely, to bend under voltage. Flexoelectricity can be present in all materials; however, the magnitude of the flexoelectric coefficients is so small that flexoelectricity is virtually imperceptible on the human scale. The book's objective is to look at the flexoelectric effect in ceramics for various applications point of view such as sensor, actuator and energy harvesting etc. It briefly discusses the flexoelectric effect theories and models with the latest development in this field. Several methods are discussed to increase the flexoelectric effect in ferroelectric and other ceramics. It focused on the latest development in various possible applications such as flexopyroelectric, flexocaloric and nano energy generators. Apart from these, it will also discuss the inverse flexoelectric effect, flexoelectric effect in 2D materials, ambiguities and controversies in this field. This book resolved many questions related to flexoelectricity and made significant discoveries with profound implications beyond flexoelectricity, in such diverse areas as caloric or MEMS devices, etc. It covers the most recent breakthroughs in nano-generator, composite-based ceramics to maximize energy harvesting and storage. Therefore, this book will be handy for a researcher working in this direction of ceramics and can be a reference book for allied specializations. It will open a new approach to using the flexoelectric effect in various ceramics and varieties of applications. - Provides an in-depth study of the flexoelectric effect of a broad range of ceramic materials - It updates the state of art progress that has been done in the area of flexoelectric-based energy harvesting via nano-generator or nanocomposites of ceramics - Provides most recent advancement in the area of lead-free, lead-based ceramics, 2D material, flexocaloric and flexopyroelectric applications - The inverse flexoelectric effect is discussed in detail, which helps newcomers and expert researchers, scientists, and engineers working in this field - Includes an evaluation of ambiguities and controversies about the flexoelectric effect

Download or read book Residual Ferroelectricity Piezoelectricity and Flexoelectricity in Barium Strontium Titanate Tunable Dielectrics written by Lauren Garten and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Loss reduction is critical to the development of Ba1-xSrxTiO3 (BST) thin film tunable microwave dielectrics. This work addresses mechanisms of loss and performance of Ba1-xSrxTiO3, such as residual ferroelectricity, enhanced flexocoupling, and dc electric field induced piezoelectricity.The presence of residual ferroelectricity --a persistent ferroelectric response above the global phase transition temperature, adds a contribution to dielectric loss from either motion of domain walls or the boundaries of micropolar regions, degrading the tunable performance over a wide frequency range. Rayleigh behavior as a function of temperature was used to track the ferroelectric behavior of BST materials through the ferroelectric to paraelectric transition temperature. The irreversible Rayleigh parameter serve as a metric for the presence of ferroelectricity because this response is dependent on the presence of domain walls, cluster boundaries or phase boundaries. Chemical solution deposited Ba0.7Sr0.3TiO3 films, with relative tunabilities of 86% over 250kV/cm at 100kHz, demonstrated residual ferroelectricity at least 65°C above the ostensible paraelectric transition temperature. The Rayleigh behavior was further corroborated with second harmonic generation, polarization-electric field hysteresis loops and the frequency dependence of the Rayleigh response. The temperature extent of residual ferroelectricity in sputtered and chemical solution deposited films and bulk ceramics was investigated as a function of chemical inhomogeneity on the A-site using electron energy loss spectroscopy. All samples showed some residual ferroelectricity, where the temperature extent was a function of the sample processing. The application of AC electric field for residual ferroelectric measurements of these samples lead to a 100% increase in loss for ac fields exceeding 10kV/cm at room temperature.The presence of residual ferroelectricity in BST also correlates to the increased flexoelectric response in these materials. Residual ferroelectricity is observed in barium strontium titanate ceramics 30°C above the global phase transition temperature, in the same temperature range in which anomalously large flexoelectric coefficients are reported. The application of a strain gradient in this temperature range was shown to lead to strain gradient-induced poling, or flexoelectric poling, enhancing the flexoelectric response. Flexoelectric poling was observed by the development of a remanent polarization in flexoelectric measurements upon the removal of the applied strain gradient. Additionally, an induced d33 piezoelectric response was observed in samples after the removal of the applied strain gradient, indicating that the polarization was realigned during flexoelectric measurements. Flexoelectric poling lead to the production of an internal bias of 9 kV/m. It is concluded that residual ferroelectric response considerably enhances the observed flexoelectric response. In order to investigate the effects of dc electric field induced piezoelectricity, metrology was designed, developed and calibrated for the measurement of the e31,f piezoelectric coefficient as a function of applied electric field and strain. This allowed for direct measurements of the field-induced piezoelectric response for Ba0.7Sr0.3TiO3 (70:30) and Ba0.6Sr0.4TiO3 (60:40) thin films on MgO and silicon. The relative dielectric tunabilities for the 70:30 and 60:40 composition on MgO were 83% and 70% respectively, with a dielectric loss of 0.011 and 0.004 at 100 kHz respectively. A linear increase in induced piezoelectricity with field to --3.0 C/m2 and --1.5 C/m2 at 110 kV/cm was observed in 60:40 BST on MgO and 70:30 BST on Si. Large and hysteretic piezoelectric and tuning responses were observed in the 70:30 BST thin films on MgO. This was consistent with the irreversible Rayleigh behavior, indicating a ferroelectric contribution to the piezoelectric and dielectric response 40°C above the global paraelectric transition temperature. This information should enable advancements in tunable dielectric components through the removal of piezoelectric resonance-based loss mechanisms.

Download or read book Atomistic and Continuum Study of Flexoelectricity in Ferroelectric Materials written by Raouf Mbarki and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, we try to address some of the questions which arise while studying flexoelectricity in ferroelectric materials. 1. Most technologically-relevant ferroelectrics typically lose piezoelectricity above the Curie temperature. This limits their use to relatively low temperatures. In this dissertation, exploiting a combination of flexoelectricity and simple functional grading, we propose a strategy for high-temperature electromechanical coupling in a standard thin film configuration. We use continuum modeling to quantitatively demonstrate the possibility of achieving apparent piezoelectric materials with large and temperature-stable electromechanical coupling across a wide temperature range that extends significantly above the Curie temperature. With Barium and Strontium Titanate as example materials, a significant electromechanical coupling that is potentially temperature-stable up to 900 C is possible. 2. Piezoelectricity is a property of non-centrosymmetric crystals. In most typically used ferroelectrics, this property is lost as the temperature is increased beyond the Curie point thus strongly reducing the availability of efficient materials that can be used for high temperature energy harvesting. Flexoelectricity, as can be shown from simple symmetry arguments, is a universal and linear electromechanical coupling that dictates the development of polarization upon application of inhomogeneous strains. The implications of this phenomenon become amplified at the nanoscale. In this dissertation, we develop a molecular dynamics approach predicated on a specially tailored interatomic force-field to extract the temperature dependence of flexoelectricity. Surprisingly, we find that it, at least for Barium Titanate and Strontium Titanate nano structures, increases with temperature. Apart from cataloging this interesting observation for future use in high temperature energy harvesting, we also examine the physical mechanisms that lead to the observed temperature dependence. 3. A new theory for 180 domain wall in ferroelectric perovskite material is presented in this work. The effect of flexoelectric coupling on the domain structure is analyzed. We show that the 180 domain wall has a mixed character of Ising and Bloch type wall and that the polarization perpendicular to the domain wall is non zero though it is very small compared to the spontaneous polarization in the case of tetragonal Barium Titanate. Finally, we present the effect of the new finding on the domain wall interaction with defects in the material. 4. Pyroelectric materials generate electricity in response to change in temperature. These materials are commonly used to build temperature sensors, radiation detectors and alarm systems, among others. There are few materials that possess this property. In this work, we develop a nonlinear theoretical framework for pyroelectricity in soft materials. Using the concept of soft electrets materials, we illustrate a nonlinear relation between the Maxwell stress effect and pyroelectricity, and propose the design of a pyroelectric material whose constituents are intrinsically non-pyroelectric.

Download or read book Flexoelectricity in Liquid Crystals written by Agnes Buka and published by World Scientific. This book was released on 2013 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.

Download or read book Piezoelectric Nanomaterials for Biomedical Applications written by Gianni Ciofani and published by Springer Science & Business Media. This book was released on 2012-03-31 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanoscale structures and materials have been explored in many biological applications because of their novel and impressive physical and chemical properties. Such properties allow remarkable opportunities to study and interact with complex biological processes. This book analyses the state of the art of piezoelectric nanomaterials and introduces their applications in the biomedical field. Despite their impressive potentials, piezoelectric materials have not yet received significant attention for bio-applications. This book shows that the exploitation of piezoelectric nanoparticles in nanomedicine is possible and realistic, and their impressive physical properties can be useful for several applications, ranging from sensors and transducers for the detection of biomolecules to “sensible” substrates for tissue engineering or cell stimulation.

Download or read book Barium Strontium Titanate written by Natheer Mahmood and published by LAP Lambert Academic Publishing. This book was released on 2014-03 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium Strontium Titanate Ba(x)Sr(1-x)TiO3 Is a solid solution between BaTiO3 and SrTiO3 which posses different Ferroelectric Curie temperature, Barium Strontium Titanate (BST) posses an adjustable value of Ferroelectric Curie temperature Tc depending on the value of (x). BST has wide range of applications depending on Curie temperature and Dielectric properties . BST used in communications especially in microwave tunable circuits, phase shifter, waveguides, antennas, MOSFET, MLCCs and Varactor.

Download or read book Barium Strontium Titanate Thin Films for Electro optic Applications written by Danyang Wang and published by . This book was released on 2006 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Characterization and Applications of Barium Strontium Titanate Thin Film Structures written by Supriya Ashok Ketkar and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium Strontium Titanate (BST) based ferroelectric thin film devices have been popular over the last decade due to their versatile applications in tunable microwave devices such as delay lines, resonators, phase shifters, and varactors. BST thin films are promising candidates due to their high dielectric constant, tunability and low dielectric loss. Dielectric-tunable properties of BST films deposited by different deposition techniques have been reported which study the effects of factors, such as oxygen vacancies, film thickness, grain size, Ba/Sr ratio, etc. Researchers have also studied doping concentrations, high temperature annealing and multilayer structures to attain higher tunability and lower loss. The aim of this investigation was to study material properties of Barium Strontium Titanate from a comprehensive point of view to establish relations between various growth techniques and the film physical and electrical properties. The primary goal of this investigation was to synthesize and characterize RF magnetron sputtered Barium Strontium Titanate (Ba1-xSrxTiO3), thin film structures and compare their properties with BST thin films deposited by sol-gel method with the aim of determining relationships between the oxide deposition parameters, the film structure, and the electric field dependence. In order to achieve higher thickness and ease of fabrication, and faster turn around time, a [grave]stacked' deposition process was adopted, wherein a thin film (around 200nm) of BST was first deposited by RF magnetron sputtering process followed by a sol-gel deposition process to achieve higher thickness. The investigation intends to bridge the knowledge gap associated with the dependence of thickness variation with respect to the tunability of the films. The film structures obtained using the three different deposition methods were also compared with respect to their analytical and electrical properties.

Download or read book Electronic Structure of Barium Strontium Titanate by Soft x ray Absorption Spectroscopy written by and published by . This book was released on 1997 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perovskite-type titanates, such as Strontium Titanate (STO), Barium Titanate (BTO), and Lead Titanate (PTO) have been widely studied because they show good electric and optical properties. In recent years, thin films of Barium Strontium Titanate (BST) have been paid much attention as dielectrics of dynamic random access memory (DRAM) capacitors. BST is a better insulator with a higher dielectric constant than STO and can be controlled in a paraelectric phase with an appropriate ratio of Ba/Sr composition, however, few studies have been done on the electronic structure of the material. Studies of the electronic structure of such materials can be beneficial, both for fundamental physics research and for improving technological applications. BTO is a famous ferroelectric material with a tetragonal structure, in which Ti and Ba atoms are slightly displaced from the lattice points. On the other hand, BST keeps a paraelectric phase, which means that the atoms are still at the cubic lattice points. It should be of great interest to see how this difference of the local structure around Ti atoms between BTO and BST effects the electronic structure of these two materials. In this report, the authors present the Ti L{sub 2,3} absorption spectra of STO, BTO, and BST measured with very high accuracy in energy of the absorption features.

Download or read book Ferroelectric Materials for Energy Applications written by Haitao Huang and published by John Wiley & Sons. This book was released on 2019-01-04 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a comprehensive overview of the emerging applications of ferroelectric materials in energy harvesting and storage Conventional ferroelectric materials are normally used in sensors and actuators, memory devices, and field effect transistors, etc. Recent progress in this area showed that ferroelectric materials can harvest energy from multiple sources including mechanical energy, thermal fluctuations, and light. This book gives a complete summary of the novel energy-related applications of ferroelectric materials?and reviews both the recent advances as well as the future perspectives in this field. Beginning with the fundamentals of ferroelectric materials, Ferroelectric Materials for Energy Applications offers in-depth chapter coverage of: piezoelectric energy generation; ferroelectric photovoltaics; organic-inorganic hybrid perovskites for solar energy conversion; ferroelectric ceramics and thin films in electric energy storage; ferroelectric polymer composites in electric energy storage; pyroelectric energy harvesting; ferroelectrics in electrocaloric cooling; ferroelectric in photocatalysis; and first-principles calculations on ferroelectrics for energy applications. -Covers a highly application-oriented subject with great potential for energy conversion and storage applications. -Focused toward a large, interdisciplinary group consisting of material scientists, solid state physicists, engineering scientists, and industrial researchers -Edited by the "father of integrated ferroelectrics" Ferroelectric Materials for Energy Applications is an excellent book for researchers working on ferroelectric materials and energy materials, as well as engineers looking to broaden their view of the field.

Download or read book Handbook of Mechanics of Materials written by Siegfried Schmauder and published by Springer. This book was released on 2019-05-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive reference for the studies of mechanical properties of materials over multiple length and time scales. The topics include nanomechanics, micromechanics, continuum mechanics, mechanical property measurements, and materials design. The handbook employs a consistent and systematic approach offering readers a user friendly reference ideal for frequent consultation. It is appropriate for an audience at of graduate students, faculties, researchers, and professionals in the fields of Materials Science, Mechanical Engineering, Civil Engineering, Engineering Mechanics, and Aerospace Engineering.

Download or read book Barium Strontium Titanate Films for Tunable Microwave and Acoustic Wave Applications written by Venkataramanan Gurumurthy and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The composition-dependent Curie temperature and bias-dependant dielectric permittivity of Barium Strontium Titanate (BST) makes it very attractive for tunable application in the RF/Microwave regime. In this research work, the performance of BST varactors fabricated on the conventional Pt/Ti/SiO2/Si bottom electrode stack were compared with those fabricated using chemical vapor deposited Nanocrystalline Diamond (NCD) as the diffusion barrier layer instead of SiO2. The varactors fabricated on NCD films displayed much better symmetry in capacitance-voltage behavior and better overall quality factors than varactors fabricated on SiO2. The improvement in performance can be attributed to existence of stable interfaces in the devices fabricated on NCD which reduced the bottom electrode losses at high frequencies. The SiO2 based BST varactors on the other hand displayed better reliability and breakdown fields. The main purpose of this research work is to develop a robust Metal Insulator Metal (MIM) structure to achieve better all round performance of BST varactors. In the second part of this research work, the prospect of developing diamond based layered Surface Acoustic Wave (SAW) devices using Ba0.8Sr0.2TiO3 as the piezoelectric layer is investigated. Structural characterization of BST thin films deposited on Si/NCD/Pt and Si/SiO2/Ti/Pt stack were performed using X-Ray Diffraction (XRD) and Atomic Force Microscopy (AFM). Cross-sectional studies on the two stacks were performed using Scanning Electron Microscopy (SEM). X-Ray Mapping (XRM) was then done to ascertain the quality of the interfaces and to check for interdiffusion between layers. MIM structures in the Coplanar Waveguide (CPW) configuration were fabricated using conventional lithography and etching techniques for high frequency measurements. The performance of the fabricated varactors was characterized from 100 MHz to 1 GHz. For the SAW application, structural characterization of Ba0.8Sr0.2TiO3 on Chemical Vapor Deposited (CVD) diamond was done and the deposition procedure was optimized to obtain thick BST films. SAW bandpass filters and resonators were designed wherein the device geometry was varied over a wide range in order to characterize the variation in device performance with geometry. Finally interdigital capacitor structures were fabricated and used for conducting Curie temperature measurements on the deposited BST films in order to determine the operation range of the deposited BST films.

Download or read book Hydrothermal Synthesis of Barium Strontium Titanate bst Powders and Continuous and Patterned Thin Films written by Xuezheng Wei and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Barium strontium titanate (BST) solid-solution oxides represent an important class of ferroelectric materials due to their high dielectric constants, composition dependent Curie temperature, and potential applications in dynamic random access memory (DRAM). Hydrothermal technique is a new low-temperature (

Download or read book Coatings and Thin Film Technologies written by Jaime Andres Perez Taborda and published by BoD – Books on Demand. This book was released on 2019-01-03 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of coatings and thin-film technologies is rapidly advancing to keep up with new uses for semiconductor, optical, tribological, thermoelectric, solar, security, and smart sensing applications, among others. In this sense, thin-film coatings and structures are increasingly sophisticated with more specific properties, new geometries, large areas, the use of heterogeneous materials and flexible and rigid coating substrates to produce thin-film structures with improved performance and properties in response to new challenges that the industry presents. This book aims to provide the reader with a complete overview of the current state of applications and developments in thin-film technology, discussing applications, health and safety in thin films, and presenting reviews and experimental results of recognized experts in the area of coatings and thin-film technologies.

Download or read book 2015 ICU International Congress on Ultrasonics Abstract Book Metz France Declercq N F editor 2015 written by Nico F. Declercq and published by Nico F. Declercq. This book was released on 2015-05-11 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The compilation of this book has been made possible with the help of Didier Cassereau, Bertrand Dubus and John Fritsch with support from the Scientific and Technical Committee of 2015 ICU.

Download or read book Ferroelectric Materials for Energy Harvesting and Storage written by Deepam Maurya and published by Woodhead Publishing. This book was released on 2020-10-14 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to more efficiently harvest energy for electronics has spurred investigation into materials that can harvest energy from locally abundant sources. Ferroelectric Materials for Energy Harvesting and Storage is the first book to bring together fundamental mechanisms for harvesting various abundant energy sources using ferroelectric and piezoelectric materials. The authors discuss strategies of designing materials for efficiently harvesting energy sources like solar, wind, wave, temperature fluctuations, mechanical vibrations, biomechanical motion, and stray magnetic fields. In addition, concepts of the high density energy storage using ferroelectric materials is explored. Ferroelectric Materials for Energy Harvesting and Storage is appropriate for those working in materials science and engineering, physics, chemistry and electrical engineering disciplines. - Reviews wide range of energy harvesting including solar, wind, biomechanical and more - Discusses ferroelectric materials and their application to high energy density capacitors - Includes review of fundamental mechanisms of energy harvesting and energy solutions, their design and current applications, and future trends and challenges