scholarly journals Perovskite Ferroelectric

2021 ◽  
Author(s):  
Paramjit Kour ◽  
Sudipta Kishore Pradhan

The spectrums of properties exhibited by ferroelectric materials are dielectric, ferroelectric, piezoelectric and pyroelectric effect. This is the makes these materials to have a wide range of useful application. Infrared detectors are used pyroelectric effect of ferroelectric materials. It is used in nonvolatile memories due to have ferroelectric hysteresis. Its piezoelectric properties make them useful for actuator, radio frequency filter, sensor, and transducer. Ferroelectric capacitors are used, their good dielectric behavior. According to the necessity of the system they are available in different form such as single crystals, ceramics, thin film, and polymer, composite. The diversity of properties ferroelectric materials always attracted the attention of engineers and researchers. Size reduction of this material from micro to nanoscale established an enormous consideration to develop nanotechnology. Its vast use of different filed imposed the in detail research in adding to the development of processing and characterization method. This chapter will put some light on some fundamental principle of ferroelectricity, the list of perovskite materials and their application.

2012 ◽  
Vol 02 (01) ◽  
pp. 1250002 ◽  
Author(s):  
DHANANJAY K. SHARMA ◽  
RAJU KUMAR ◽  
RADHESHYAM RAI ◽  
SEEMA SHARMA ◽  
ANDREI L. KHOLKIN

In this paper, we present impedance spectroscopy of Sodium Bismuth Titanate-based materials belonging to (1-x) Na 1/2 Bi 1/2 TiO 3-x BaTiO 3(x = 0.04) (NBT–BT) system. NBT–BT ceramics are prepared by high temperature solid-state reaction method. X-ray diffraction technique showed single-phase polycrystalline sample with an ABO3 perovskite structure. Dielectric behavior and the impedance relaxation were investigated in a wide range of temperature (room temperature (RT) –500°C) and frequency (1 kHz–1 MHz). A broad dielectric constant peak was observed over a wide temperature range around the phase transition temperature. The complex impedance plot exhibited one impedance semicircle identified over the frequency range of 1 kHz–1 MHz, which is explained by the grain effect of the bulk. The centers of the impedance semicircles lie below the real axis, which indicates that the impedance response is a Cole–Cole type relaxation.


2019 ◽  
Vol 43 (3) ◽  
pp. 96-140 ◽  
Author(s):  
Dominic D.P. Johnson ◽  
Dominic Tierney

A major puzzle in international relations is why states privilege negative over positive information. States tend to inflate threats, exhibit loss aversion, and learn more from failures than from successes. Rationalist accounts fail to explain this phenomenon, because systematically overweighting bad over good may in fact undermine state interests. New research in psychology, however, offers an explanation. The “negativity bias” has emerged as a fundamental principle of the human mind, in which people's response to positive and negative information is asymmetric. Negative factors have greater effects than positive factors across a wide range of psychological phenomena, including cognition, motivation, emotion, information processing, decision-making, learning, and memory. Put simply, bad is stronger than good. Scholars have long pointed to the role of positive biases, such as overconfidence, in causing war, but negative biases are actually more pervasive and may represent a core explanation for patterns of conflict. Positive and negative dispositions apply in different contexts. People privilege negative information about the external environment and other actors, but positive information about themselves. The coexistence of biases can increase the potential for conflict. Decisionmakers simultaneously exaggerate the severity of threats and exhibit overconfidence about their capacity to deal with them. Overall, the negativity bias is a potent force in human judgment and decisionmaking, with important implications for international relations theory and practice.


Nanoscale ◽  
2021 ◽  
Author(s):  
Keonwon Beom ◽  
Jimin Han ◽  
Hyun-Mi Kim ◽  
Tae-Sik Yoon

Wide range synaptic weight modulation with a tunable drain current was demonstrated in thin-film transistors (TFTs) with a hafnium oxide (HfO2−x) gate insulator and an indium-zinc oxide (IZO) channel layer...


2001 ◽  
Vol 16 (2) ◽  
pp. 239-293 ◽  
Author(s):  
Barbara Kwiatkowska

AbstractThe Southern Bluefin Tuna (Jurisdiction and Admissihilily) Award of 4 August 2000 marked the first instance of the application of compulsory arbitration under Part XV, Section 2 of the 1982 UN Law of the Sea Convention and of the exercise by the Annex VII Tribunal of la compétence de la compétence pursuant to Article 288(4) over the merits of the instant dispute. The 72-paragraph Award is a decision of pronounced procedural complexity and significant multifaceted impacts of which appreciation requires an in-depth acquaintance with procedural issues of peaceful settlement of disputes in general and the-law-of-the-sea-related disputes in particular. Therefore, the article surveys first the establishment of and the course of proceedings before the five-member Annex VII Arbitral Tribunal, presided over by the immediate former ICJ President, Judge Stephen M. Schwebel, and also comprising Judges Keith, Yamada. Feliciano and Tresselt. Subsequently, the wide range of specific paramount questions and answers of the Tribunal are scrutinised against the background of arguments advanced by the applicants (Australia and New Zealand) and the respondent (Japan) during both written and oral pleadings, including in reliance on the extensive ICJ jurisprudence and treaty practice concerned. On this basis, the article turns to an appraisal of the impacts of the Arbitral Tribunal's paramount holdings and its resultant dismissal of jurisdiction with the scrupulous regard for the fundamental principle of consensuality. Amongst such direct impacts as between the parties to the instant case, the inducements provided by the Award to reach a successful settlement in the future are of particular importance. The Award's indirect impacts concern exposition of the paramount doctrine of parallelism between the umbrella UN Convention and many compatible (fisheries, environmental and other) treaties, as well as of multifaceted, both substantial and procedural effects of that parallelism. All those contributions will importantly guide other courts and tribunals seised in the future under the Convention's Part XV, Section 2.


2021 ◽  
Vol 3 (108) ◽  
pp. 26-41
Author(s):  
Beata Mrozowska - Bartkiewicz

A mutual insurance society is one of the basic forms of conducting insurance activity. It is characterized by a very wide range of options which its founders and subsequently entitled members have in order to choose the organizational and systemic model of operation, to change it in the course of business, to define the concept of membership, to create various categories of members and provide them with different rights and duties, to determine the powers of statutory bodies, and, above all, to apply the method of mutuality. The Insurance and Reinsurance Activity Act regulates the basic legal framework of mutual companies, while referring quite a number of issues to the Polish Commercial Partnerships and Companies Code. This does not alter the fundamental principle on which the company's activity is based, namely that its articles of association play an extremely important role, which is much greater than in the case of public limited liability companies, and that members of a mutual insurance society enjoy considerable freedom to conduct business and categorize its members, which is unparalleled for other legal forms of business activity.


Nanoscale ◽  
2021 ◽  
Author(s):  
David Esseni ◽  
Riccardo Fontanini

The negative capacitance (NC) operation of ferroelectric materials has been originally proposed based on a homogeneous Landau theory, leading to a simple NC stabilization condition expressed in terms of macroscopic...


2002 ◽  
Vol 718 ◽  
Author(s):  
A.A. Savvinov ◽  
S.B. Majumder ◽  
R.S. Katiyar

AbstractThe renewed interest in KTa1-xNbxO (KTN) mixed perovskite materials is connected with their remarkable dielectric properties in the dilute compositions. KTN thin films with x = 0.35 have been prepared on different substrates by sol-gel technique as well as a set of powders with x = 0, 0.05, 0.1, 0.25, 0.48, 0.65, 0.75, and 1. Properties of the material change drastically with the change of x, because of relaxation of both translational and inversion symmetry due to a static disorder in the Nb distribution and the dynamic effect of a precursor ferroelectric order above Tc. Special attention was paid to the characteristic feature of coupling of the single-phonon state to a two-acoustic-phonon feature through anharmonic terms in the potential function as well as behavior of the TO3 mode which becomes a narrow peak of the first-order scattering in the tetragonal ferroelectric phase and shows a tendency to split below Tc2 in the orthorhombic phase. The wide range of x allows better understanding of dynamic processes in the KTN bulk materials which in turn helps in the studies of thin films. The above mentioned materials were studied using Raman scattering, XRD, and thermal analysis techniques.


2000 ◽  
Vol 15 (12) ◽  
pp. 2758-2769 ◽  
Author(s):  
Michael Lane ◽  
Reinhold H. Dauskardt ◽  
Anna Vainchtein ◽  
Huajian Gao

The effects of plasticity in thin copper layers on the interface fracture resistance in thin-film interconnect structures were explored using experiments and multiscale simulations. Particular attention was given to the relationship between the intrinsic work of adhesion, Go, and the measured macroscopic fracture energy, Gc. Specifically, the TaN/SiO2 interface fracture energy was measured in thin-film Cu/TaN/SiO2 structures in which the Cu layer was varied over a wide range of thickness. A continuum/FEM model with cohesive surface elements was employed to calculate the macroscopic fracture energy of the layered structure. Published yield properties together with a plastic flow model for the metal layers were used to predict the plasticity contribution to interface fracture resistance where the film thickness (0.25–2.5 μm) dominated deformation behavior. For thicker metal layers, a transition region was identified in which the plastic deformation and associated plastic energy contributions to Gc were no longer dominated by the film thickness. The effects of other salient interface parameters including peak cohesive stress and Go are explored.


2019 ◽  
Author(s):  
Jose J Plata ◽  
Javier Amaya Suárez ◽  
Santiago Cuesta-López ◽  
Antonio Marquez ◽  
Javier Fdez. Sanz

<div> <div> <div> <p>Conventional solar cell efficiency is usually limited by the Shockley-Queisser limit. This is not the case, however, for ferroelectric materials, which present a spontaneous electric polarization that is responsible for their bulk photovoltaic effect. Even so, most ferroelectric oxides exhibit large band gaps, reducing the amount of solar energy that can be harvested. In this work, a high-throughput approach to tune the electronic properties of thin-film ferroelectric oxides is presented. Materials databases were systematically used to find substrates for the epitaxial growth of KNbO3 thin-films, using topological and stability filters. Interface models were built and their electronic and optical properties were predicted. Strain and substrate-thin-film band interaction effects were examined in detail, in order to understand the interaction between both materials. We found substrates that significantly reduce the KNbO3 band gap, maintain KNbO3 polarization, and potentially present the right band alignment, favoring the electron injection in the substrate/electrode. This methodology can be easily applied to other ferroelectric oxides, optimizing their band gaps and accelerating the development of new ferroelectric-based solar cells. </p> </div> </div> </div>


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