scholarly journals Electrical and Dielectric Characterization of Bi12GeO20Prepared by Modified Pechini Method

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
C. G. P. Moraes ◽  
F. A. A. Jesus ◽  
Z. S. Macedo

Bismuth germanate (Bi12GeO20) ceramics were produced using modified Pechini route, and the synthesis parameters, crystalline phases, microstructure, and sintering conditions were investigated.Bi12GeO20powders with submicrometric particle sizes were investigated for calcination temperatures from 400 to 600°C, with soaking times of 1 h and 5 h. Controlling the synthesis parameters, dense ceramics with two different grain sizes of 3.4 ± 0.5 µm and 5.7 ± 0.8 µm could be produced after sintering at 750°C/1 h. The electric and dielectric properties of these ceramics were determined by impedance spectroscopy (IS). From the results, it was concluded that the dielectric permittivity measured at high frequencies is insensitive to the grain size, while the AC dark conductivity presents a noticeable dependency on this feature. This behaviour was discussed on the basis of a Maxwell-Wagner interfacial relaxation, whose intensity depends directly on the volume fraction of grain boundaries in the sample.

2011 ◽  
Vol 197-198 ◽  
pp. 456-459
Author(s):  
Xian Ming Liu ◽  
Wen Liang Gao

Spinel-perovskite multiferroics of NiFe2O4/BiFeO3 nanoparticles were prepared by modified Pechini method. The structure and morphology of the composites were examined by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the composites consisted of spinel NiFe2O4 and perovskite BiFeO3 after annealed at 700°C for 2h, and the particle size ranges from 40 to 100nm. VSM and ME results indicated that the nanocomposites exhibited both tuning magnetic properties and a ME effect. The ME effect of the nanocomposites strongly depended on the magnetic bias and magnetic field frequency.


2019 ◽  
Vol 822 ◽  
pp. 334-342
Author(s):  
Aleksander Semencha ◽  
Elena V. Bochagina ◽  
Margarita G. Dronova

The work investigates the characteristics of the porosity of inorganic salts: magnesium silicate and yttrium aluminum garnet (YAG). Using the example of nanocrystalline powders of magnesium silicate and yttrium aluminum garnet, the effect of synthesis parameters on the phase composition and porous characteristics of the obtained powders was studied. The average pore size of adsorbents was obtained: magnesium silicate - 48 nm; YAG, obtained by the standard Pechini method – 44 nm; YAG, obtained by the modified Pechini method – 37 nm; the industrial brand “magnesol” – 32 nm. The resulting materials can be attributed to mesoporous adsorbents.


2009 ◽  
Vol 53 (2) ◽  
pp. 390-398 ◽  
Author(s):  
Abdul Majid ◽  
James Tunney ◽  
Steve Argue ◽  
David Kingston ◽  
Michael Post ◽  
...  

2012 ◽  
Vol 64 (1) ◽  
pp. 78-85 ◽  
Author(s):  
M. P. F. Graça ◽  
P. R. Prezas ◽  
M. M. Costa ◽  
M. A. Valente

2018 ◽  
Vol 84 (1) ◽  
pp. 10201 ◽  
Author(s):  
Mounir Bouchaour ◽  
Juan Pablo Martínez Jiménez ◽  
Nacerdine Bouzit ◽  
Nacerdine Bourouba

The main objective of this paper is to study the dielectric behavior of a quaternary composite, made from a mixture of barium titanate (BT), manganese dioxide (MnO2) and calcium oxide (CaO) in the same epoxy resin matrix (RE) maintained at 70% by volume fraction, while those of the other constituents are variable and completing each other in a way to achieve the remaining proportion, i.e. 30%. Random mixtures are made at room temperature and under atmospheric pressure. A dielectric characterization of this mixture type was performed by time-domain spectroscopy (TDS) over a frequency wide band (DC–2 GHz). This has been carried out to illustrate the effect of two oxides (MnO2 and CaO) simultaneously at low frequency (500 MHz), in the presence of (BT), on the composite dielectric behavior. This has led consequently to make a comparison between the present acquired results and those of the ternary composite, where (MnO2) and (CaO) act separately. The results obtained so far in this study allowed us to check the validity of the modified Lichtenecker law (MLL)-based predictive model in the quaternary composite case. The interest of this study lies on applications of these materials in microelectronics circuits and absorber materials in telecommunication domain.


1995 ◽  
Vol 10 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Cem Basceri ◽  
A. Cuneyt Tas ◽  
Muharrem Timucin

New solid solution phases in the (Y,Ca)(Cr,Co)O3 system have been synthesized and characterized by powder X-ray diffraction. The selected compositions in this system were prepared by the modified Pechini method. Powder-diffraction patterns were prepared.


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