Ceramics Mn2
Mostrando 1-7 de 7 artigos, teses e dissertações.
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1. Grain-Boundary Resistance and Nonlinear Coefficient Correlation for SnO2-Based Varistors
This work has focused on the electrical and microstructural properties of Nb2O5-doped SnO2-MnO2 ceramics. The pellets were prepared by solid-state reaction method according to the system (99.5-x) SnO2 - 0.5 MnO2 - x Nb2O5, on the following molar ratio x = 0.05; 0.10; 0.15; 0.20 and 0.25. Scanning electron microscopy and electrical measurements (ac and dc) we
Mat. Res.. Publicado em: 26/09/2016
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2. 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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3. PROPRIEDADES VIBRACIONAIS E DIELÉTRICAS DA MULITA Bi2Mn4O10 / VIBRATIONAL PROPERTIES AND DIELECTRIC OF MULITA Bi2Mn4O10
In this work we investigated the vibrational properties of ceramics Bi2Mn4O10 (BMO) at room temperature by the Raman and Infrared spectroscopies, the phonons were classified by FG matrix method of Wilson. The dielectric properties of the material, in turn, were studied using the impedance spectroscopy in a range of 22 C to 275 C. Furthermore, static atomisti
Publicado em: 2010
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4. Spectroscopies of photoluminescence and excitation of MgGa2O4 samples doped with Mn2+. / Espectroscopia de fotoluminescência e excitação de amostras MgGa2O4 dopadas com Mn2+
This work presents the room temperature photoluminescence and excitation spectroscopes data of MgGa2O4 samples doped with 0.5% and 10.0% Mn2+. The polycrystalline samples were produced by solid-state reaction at high temperature and characterized with X ray Diffraction and SEM. The photoluminescence spectra showed emission at green and red spectral regions,
Publicado em: 2009
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5. The effect of Cr concentration and preparation method on the microstructure and electrical characterization of SnO2-based ceramics
This paper reports a study of the influence of Cr concentration and preparation method in the electrical conductivity and microstructure of SnO2-based powders doped with Mn and Nb, prepared by an organic route (Pechini method) and a mixture of oxides. All the samples were compacted into discs and sintered at 1300 °C for 3h, resulting in ceramics with relati
Materials Research. Publicado em: 2003-12
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6. Nonohmic behavior of SnO2.MnO2-based ceramics
The present paper describes the nonohmic behavior of the SnO2.MnO-based system and analyzes the influence of the sintering time and the Nb2O5 concentration on this system's electrical properties. A nonlinear coefficient of ~7 was obtained for a 0.2 mol%-doped Nb2O5 composition, which is comparable to other values reported in the literature for the ternary Sn
Materials Research. Publicado em: 2003-06
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7. Caracterização de sistemas varistores a base de SnO2-MnO2. / Characterization of varistors systems SnO2-MnO2 based.
This work focussed on the effect of addition of Nb2O5 on the electrical and microestructural properties of SnO2-MnO2 based ceramics. It was also studied the effect of heat-treatments in a oxygen-rich atmosphere in these properties. The parent system was 99,5% SnO2-0,5% MnO2 in molar ratio, a dense system that did not present non-ohmic behavior. The addition
Publicado em: 2002