Ferroelectric Material
Mostrando 1-12 de 28 artigos, teses e dissertações.
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1. Piezoelectricity from Elastic and Dielectric Measurements on Unpoled Ferroelectrics
A method is described to assess the piezoelectric response of ferroelectric materials from the temperature dependence of the elastic moduli and dielectric constant of unpoled samples. The limits and advantages over the traditional methods on poled samples are discussed. A quantitative check is made by comparing the piezoelectric softening measured below the
Mat. Res.. Publicado em: 07/06/2018
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2. Ba-DOPED ZnO MATERIALS: A DFT SIMULATION TO INVESTIGATE THE DOPING EFFECT ON FERROELECTRICITY
ZnO is a semiconductor material largely employed in the development of several electronic and optical devices due to its unique electronic, optical, piezo-, ferroelectric and structural properties. This study evaluates the properties of Ba-doped wurtzite-ZnO using quantum mechanical simulations based on the Density Functional Theory (DFT) allied to hybrid fu
Quím. Nova. Publicado em: 2016-04
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3. Impedance and Modulus Spectroscopy Characterization of Tb modified Bi0.8A0.1Pb0.1Fe0.9Ti0.1O3 Ceramics
In this paper we present the impedance spectroscopy of ternary solid solutions of BiFeO3, TbFeO3 and PbTiO3, prepared by solid-state reaction method. The preliminary structural studies were carried out by x-ray diffraction technique, showing the formation of polycrystalline sample with ABO3 type of perovskite structure with hexagonal symmetry for Bi0.8Tb0.1P
Mat. Res.. Publicado em: 16/02/2016
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4. Effect of ZnO addition on the structure, microstructure and dielectric and piezoelectric properties of K0.5Na0.5NbO3 ceramics
Microstructure, structure and electrical and dielectric properties of ZnO-doped K0.5Na0.5NbO3 (KNN) ceramics were investigated. Powders were obtained by the conventional solid-state method. Samples doped with 0 to 1 mol% of ZnO were sintered at 1125 °C for 2 h. Through XRD spectra, the perovskite structure was detected, in addition to small peaks correspond
Mat. Res.. Publicado em: 29/04/2014
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5. Preparation and characterization of PbTi0(3) ceramics modified by a natural mixture of rare earth oxides of xenotime
Lead titanate ceramics modified by xenotime (Xm) with nominal composition (Pb, Xm)TiO3, Xm 10 or 15 mol %, were prepared by the conventional oxide mixture technique. Xenotime is a natural mineral consisting of a mixture of rare earth oxides. Thermal, structural and electric properties were investigated through differential and gravimetric thermal analysis, X
Mat. Res.. Publicado em: 23/08/2013
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6. Preparação e Caracterização de Pós e Filmes De PbTiO3 obtidos pelo Método Pechini / Preparation and Characterization of Powders and Films From PbTiO3 obtained by Pechini method
Non-crystalline materials, commonly referred to as amorphous materials have attracted great interest in engineering and technology. This is due mainly to its photoluminescent properties at room temperature around 25 C. The aim of this study was the Pechini method in order to obtain ceramic powders and amorphous films of amorphous lead titanate. The lead tita
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/02/2012
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7. Pyroelectric composite film for X-ray intensity detection
Composite material obtained with modified lead titanate (Pz34) ferroelectric ceramic and polyether-ether-ketone (PEEK) polymer matrix was used as sensitive component to measure X-ray intensity in a novel detection system. The sensing element works as a thermal transducer, converting a non-quantified thermal flux into an output measurable quantity of electric
Materials Research. Publicado em: 15/03/2012
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8. Domínios ferroelétricos em cerâmicas e materiais nanoestruturados: investigação por microscopia de piezoresposta
In this work, ferroelectric domain structure was investigated by Piezoresponse Force Microscopy (PFM). To this, an Atomic Force Microscope (AFM) has been modified to use it as PFM at room temperature and at high temperatures. Ferroelectric ceramics were used in the as bulk ceramic samples of Pb(Zr0,40Ti0,60)O3 (PZT 40/60) and (Pb0,79La0,21)TiO3 (PLT 21) prod
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/12/2011
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9. Synthesis and characterization of PB IND.1-XR IND.XZR IND.0,40TI IND.0,60O IND.3(R = La, Ba) / Síntese e caracterização estrutural e dielétrica de compostos ferroelétricos PB IND.1-XR IND.XZR IND.0,40TI IND.0,60O IND.3(R = La, Ba)
O titanato e zirconato de chumbo PB(ZR1-yTIy)O IND.3é um material ferroelétrico de estrutura perovskita que tem sido aplicado como transdutores, amplificadores, sensores piezoelétricos, piroelétricos e memórias ferroelétricas. É bem estabelecido que a incorporação de íons de LA POT.3+ou BA POT.2+nos sítios ocupados pelo PBno sistema PB(ZR1-yTIy)O(
Publicado em: 2011
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10. Síntese, caracterização elétrica e estrutural de cerâmicas ferroelétricas de composição Ba0,90R0,10Ti1-xZrxO3 (R=Ca, Sr) / Synthesis, electric and structural characterization of Ba0,90R0,10Ti1-xZrxO3 (R= Ca, Sr) ferroelectric ceramic system
O presente trabalho teve como objetivo o estudo das propriedades elétricas e estruturais das amostras cerâmicas pertencentes ao sistema Ba1-xRxTi1-yZryO3 (R=Ca,Sr). As amostras na forma de pó micro ou nanoestruturadas foram respectivamente obtidas através do método de mistura de óxidos e do método dos precursores poliméricos. Amostras cerâmicas apre
Publicado em: 2010
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11. Estudo das transiÃÃes de fase do RbBi0,31 3Nd0,02 W8/3O9, submetido a variaÃÃes de pressÃo hidrostÃtica e temperatura. / Studies of phase transitions of RbBi0,313Nd0,02W8/3O9 submit variation of hydrostatic pressure en temperature
Tungsten bronzes has attracted great attention owing to it is interesting physical properties. Hexagonal tungsten of the form AxWO3 (with A = K, Rb, Cs), are well know superconductors. The RbBi1/3W8/3O9 (RBW) material, belongs to the valence balanced hexagonal tungsten materials with ABxW3-xO9 stoichiometry (with A = Cs, K, Rb, Tl, and B = Bi, Nd, Ta, Zr, Sc
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/02/2009
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12. Cation size effects-modified phase and PTCR development in Er3+ and Ca2+ co-doped BaTiO3 ceramics during sintering
Development of the positive temperature coefficient of resistivity (PTCR) in Er3+ and Ca2+ co-doped ferroelectric BaTiO3 was studied in this work, with Er3+ being used to act as a donor doping. Irrespective of all the materials showing high densities after sintering at 1200 to 1300 ºC, these revealed insulator at the lowest sintering temperature, changing t
Materials Research. Publicado em: 2009-09