scholarly journals Effects of V2O5 Additive on Structure and Dielectric Properties of BiNbO4 Ceramics

2013 ◽  
Vol 58 (4) ◽  
pp. 1387-1390
Author(s):  
A. Lisińska-Czekaj ◽  
D. Czekaj ◽  
K. Osińska ◽  
M. Adamczyk

Abstract Goal of the present research was to investigate the influence of V2O5 additive on the structure and dielectric properties of BiNbO4 ceramics. To fabricate BiNbO4 ceramics with V2O5 added the solid state reaction route and pressureless sintering was utilized. Thus obtained ceramics was characterized in terms of its microstructure (SEM), chemical composition (EDS), phase composition and crystalline structure (X-ray phase and structural analysis, respectively). Also dielectric properties in both temperature and frequency domains were investigated. The impedance spectroscopy was utilized for dielectric characterization and the measurements of complex impedance were performed within the frequency range ν =10Hz-1MHz and temperature range T =RT-550°C. It was found that V2O5 additive changed slightly lattice parameters of BiNbO4 ceramics, decreased porosity of samples and revealled relaxation phenomena within the frequency ranges ν =102-103 Hz and ν =105-106 Hz at temperature T>285°C.

2014 ◽  
Vol 602-603 ◽  
pp. 683-688
Author(s):  
Dionizy Czekaj ◽  
Agata Lisińska-Czekaj

Goal of the present research was to study dielectric properties of BiNbO4 ceramics fabricated by solid state reaction route followed with pressureless sintering. The samples were fabricated from the mixture of oxides, viz. Nb2O5 and Bi2O3. Apart from stoichiometric amount an excess of 3%, 5% and 10% by mole of Bi2O3 was used. It was found that an excess amount of Bi2O3 oxide caused formation of Bi5Nb3O15 minor phase in amount of 9wt%, 18wt% and 25wt%, respectively. The dielectric properties were studied by impedance spectroscopy within the frequency range ν=20Hz1MHz and temperature range T=RT550°C. It was found that the presence of the minor phase in amount of 18wt% caused a decrease in dielectric losses of the material under studies.


2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Rekha Rani ◽  
Parveen Kumar ◽  
J. K. Juneja ◽  
K. K. Raina ◽  
Chandra Prakash

We report studies on dielectric properties of magnetoelectric composites of La-substituted lead zirconate titanate (PLZT) and zinc-doped nickel ferrite (NZF) with compositional formula 0.95 Pb1-3x/2LaxZr0.65Ti0.35O3-0.05 Ni0.8Zn0.2Fe2O4(, 0.01, 0.02, and 0.03). The materials were synthesized by conventional solid state reaction route. The presence of individual phases (PLZT and NZF) was confirmed by using X-ray diffraction technique. Dielectric properties were studied as a function of temperature and frequency. Significant improvement was observed in dielectric properties with addition of La.


RSC Advances ◽  
2016 ◽  
Vol 6 (103) ◽  
pp. 101571-101577 ◽  
Author(s):  
Yan Chen ◽  
Yimin Cui ◽  
Jun-en Yao

Fe-doped La1−xFexTiO3+δ (x = 0.05, 0.1, and 0.3, 0.4) ceramic samples were prepared via traditional solid-state reaction route, in which the dielectric properties of visible light modulation were found at room temperature in the measured frequency range.


Author(s):  
Wilhelm Klein ◽  
Hanpeng Jin ◽  
Viktor Hlukhyy ◽  
Thomas F. Fässler

The crystal structure of the title compound was previously reported with composition `Pd20Sn13' [Sarahet al.(1981).Z. Metallkd,72, 517–520]. For the original structure model, as determined from powder X-ray data, atomic coordinates from the isostructural compound Ni13Ga3Ge6were transferred. The present structure determination, resulting in a composition Pd6.69Sn4.31, is based on single crystal X-ray data and includes anisotropic displacement parameters for all atoms as well as standard uncertainties for the atomic coordinates, leading to higher precision and accuracy for the structure model. Single crystals of the title compound were obtainedviaa solid-state reaction route, starting from the elements. The crystal structure can be derived from the AlB2type of structure after removing one eighth of the atoms at the boron positions and shifting adjacent atoms in the same layer in the direction of the voids. One atomic site is partially occupied by both elements with a Pd:Sn ratio of 0.38 (3):0.62 (3). One Sn and three Pd atoms are located on special positions with site symmetry 2. (Wyckoff letter 3aand 3b).


2009 ◽  
Vol 64 (7) ◽  
pp. 875-878 ◽  
Author(s):  
Hamdi Ben Yahia ◽  
Etienne Gaudin ◽  
Jacques Darriet

The new compound AgMnPO4 has been synthesized by a solid-state reaction route. Its crystal structure was determined from single-crystal X-ray diffraction data. AgMnPO4 crystallizes with triclinic symmetry, space group P1̄, a = 9.6710(6), b = 5.695(2), c = 6.629(3) Å , α = 102.55(3), β = 105.85(2), γ = 80.70(2)◦, and Z = 4. Its structure is built up from MnO6, MnO5 and PO4 polyhedra forming tunnels filled with silver atoms.


2013 ◽  
Vol 80 (12) ◽  
Author(s):  
Niels Haandbæk ◽  
Sebastian C. Bürgel ◽  
Flavio Heer ◽  
Andreas Hierlemann

AbstractThis article presents a novel microfluidic impedance cytometer enabling dielectric characterization of single cells at frequencies up to 500 MHz. The dielectric properties of cells at lower frequencies contain information about their size and membrane capacitance. The increased frequency range of the presented cytometer potentially allows for characterization of intracellular components, such as vacuoles or the cell nuclei. We demonstrate the overall capabilities of the cytometer through discrimination of polystyrene beads from Chinese hamster ovary (CHO) cells. The discrimination is based on the difference in dielectric properties at frequencies up to 500 MHz.


2016 ◽  
Vol 61 (2) ◽  
pp. 881-886 ◽  
Author(s):  
A. Lisińska-Czekaj ◽  
M. Lubina ◽  
D. Czekaj ◽  
M. Rerak ◽  
B. Garbarz-Glos ◽  
...  

Abstract Aim of the present research was to apply a solid state reaction route to fabricate Aurivillius-type ceramics described with the formula Bi6Fe2Ti3O18 (BFTO) and reveal the influence of processing conditions on its crystal structure. Pressureless sintering in ambient air was employed and the sintering temperatures were 850 and 1080 °C. It was found that the fabricated BFTO ceramics were multiphase ones. They consisted of two Bim+1Fem-3Ti3O3m+3 phases, namely the phase with m=5 (i.e. the stoichiometric phase) and m=4 (i.e. the phase with a reduced number of layers in the slab). Detailed X-ray diffraction patterns analysis showed that both phases adopted the same orthorhombic structure described with Fmm2 (42) space group. The ratio of weight fractions of the constituent phases (m=5): (m=4) was ~30:70.


Perovskite solid solutions (La0.70Ca0.30)(FexMn1-x)O3 where x = 0.01, 0.20, 0.30 and 0.40 ceramics were synthesized by solid state reaction route. The structural studies were carried by X-Ray diffraction method and the observed results have indicated that all the prepared samples were crystallized into single phase. The surface morphology was studied by Scanning Electron Microscopy and the images have revealed that grain size has increased with the increasing concentration of Fe. Archimedes principle was used to calculate the density of all the sintered samples and the density values were observed to be in increasing order. The impedance and dielectric properties have been characterized at different ranges of temperature and frequency. The value of electrical conductivity were found to be more than 100 S cm-1 , which indicate that the synthesized material is suitable material for cathode of Solid Oxide Fuel Cell.


2011 ◽  
Vol 2011 (1) ◽  
pp. 000740-000746 ◽  
Author(s):  
Bradley Thrasher ◽  
Deepukumar Nair ◽  
James Parisi ◽  
Glenn Oliver ◽  
Michael A. Smith

Low Temperature Co-fired Ceramic (LTCC) material systems offer a highly versatile microwave and millimeter wave packaging platform. Extremely low microwave loss, excellent control of dielectric constant, uniform dielectric thickness, non-existent water absorption leading to very high hermeticity, ability to support multilayer structure leading to 3-dimensional packaging, ability to embed passive functions within the tape layers, availability of a wide range of metallizations, etc. are some of the key advantages of LTCC for microwave packaging. One of the important parameters which needs to be determined at the very early stages of circuit designs are the dielectric properties - dielectric constant and loss tangent, both of which are functions of frequency. These properties need to be known accurately over the entire frequency range of operation for the circuit. For LTCC based designs, the use of dielectric constant of bulk material can lead to deviations between the performance expected at the design stage and for the fabricated circuit. Such deviations are a significant concern for broadband circuits as well as for circuits with sharp resonant behavior such as filters. One of the significant sources of deviation between bulk LTCC and “in-circuit” dielectric constant is the nature of the thick film metallizations used in LTCC technology. Work described here is a comprehensive characterization of three DuPont™ GreenTape™ LTCC systems 951, 943, and 9K7 - in the frequency range 10 to 70 GHz. Both bulk and “in-circuit” dielectric properties with silver and gold metallizations are studied to quantify the deviations in dielectric properties. A Fabry-Perot open resonator technique is used for the bulk characterization while printed ring resonators are used for the in-circuit characterization. This comprehensive characterization will provide key design data for LTCC designers in the 10 – 70 GHz frequency range.


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