Ferroelectric
Mostrando 1-12 de 74 artigos, teses e dissertações.
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1. Study of Structural and Electric Properties of the PZT 52/48 Doped With Er+3
The scientific community has shown a growing interest in relating to the ferroelectric materials and it has made an effort to develop them. Among these several ferroelectric materials, we proposed to investigated Pb(ZrTi)O3 doped with distinct Er+3 concentrations. Our aim was to investigate how the erbium affects the PZT electrical properties. To determine t
Mat. Res.. Publicado em: 25/11/2019
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2. The Modification of (Nd0.5Ta0.5)4+ Complex-Ions on Structure and Electrical Properties of Bi0.5Na0.5TiO3-BaTiO3 Ceramics
The (Bi0.5Na0.5)0.94Ba0.06Ti1-x (Nd0.5Ta0.5) xO3 (0.01≤x≤0.05) lead-free ceramics (BNBT-xNT) used (Nd0.5Ta0.5)4+ complex-ions to modify its structure and electrical properties. The BNBT-xNT ceramics exhibit the coexistence of tetragonal and rhombohedral phase. The (Nd0.5Ta0.5)4+ complex-ions prohibit grain growth, and its average grain size decreases fro
Mat. Res.. Publicado em: 14/03/2019
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3. Síntese da perovskita [KNbO3]0,9[BaNi0,5Nb0,5O3-δ]0,1 por combustão em solução
Resumo O desenvolvimento de perovskitas ferroelétricas capazes de absorver a luz visível, particularmente KBNNO - [KNbO3]0,9[BaNi0,5Nb0,5O3-δ]0,1 (band-gap Eg= 1,39 eV), tem encorajado a aplicação desses materiais na camada ativa de células solares. Em dispositivos fotovoltaicos, esses materiais podem permitir a obtenção de voltagens superiores à ma
Cerâmica. Publicado em: 2019-01
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4. A Comparative Analysis of BaTiO3/(Ba,Sr)TiO3 and BaTiO3/(Ba,Sr)TiO3/SrTiO3 Artificial Superlattices via Raman Spectroscopy
BaTiO3/Ba50Sr50TiO3 and BaTiO3/Ba50Sr50TiO3/SrTiO3 superlattices are characterized via Raman spectroscopy. Special attention is paid to a comprehensive analysis of their polarized Raman spectra, especially, within a soft mode (E(1TO)) range. The shift of E(1TO) soft mode is found to be more pronounced for BaTiO3/Ba50Sr50TiO3/SrTiO3 sample than for BaTiO3/Ba5
Mat. Res.. Publicado em: 14/11/2018
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5. 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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6. Local piezo-response for lead-free Ba0.9Ca0.1Ti0.9Zr0.1O3 electro-ceramic by switching spectroscopy
The purpose of this work is to determine the effective piezoelectric coefficient (d33) and the macro ferroelectric hysteresis behavior for the Ba0.9Ca0.1Ti0.9Zr0.1O3 (BCZT). The sample was prepared by the modified Pechini method and it was sintered at 1250 ºC for 5 h. The refinements of X-ray diffraction (XRD) patterns obtained by the Rietveld method sugges
Mat. Res.. Publicado em: 11/01/2018
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7. 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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8. 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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9. Effect of magnetic ion doping on structural, electric and relaxor properties of Pb (Fe2/3W1/3) O3 multiferroic ceramics
Single-phase Pb(Fe2/3W1/3)O3 (PFW) multiferroic ceramics doped with magnetic ions were fabricated using a modified B-site precursor method. Dielectric response was investigated over a wide range of temperature and frequency. Doping did not modify the characteristic temperatures (T C, T N) and the order at ferroelectric phase transition, keeping the relaxor p
Mat. Res.. Publicado em: 2014-12
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10. 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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11. 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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12. Electrophoretic deposition of BaTi0.85Zr0.15O3 nanopowders
The present study reports the results of thick films (20-130 µm) produced through electrophoretic deposition of BaTi0.85Zr0.15O3 (BTZ) nanometric powders synthesized by the Pechini's method. The BTZ powderscalcined at 600°C/2h presented a single crystalline phase with an average particle size of ~20nm. To thick films deposition, a stable suspension of acet
Mat. Res.. Publicado em: 29/07/2013