Dielectric Behaviour Of BaTiO3 Prepared By Sol–Gel Technique When Exposed To Different Oxygen Concentrations

2012 ◽  
Author(s):  
Cheow Keat Yeoh ◽  
Srimala Sreekantan ◽  
Sabar Derita Hutagalung ◽  
Zainal Arifin Ahmad
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Sol Gel ◽  
Chemical Processes ◽  
Oxygen Stoichiometry ◽  
Solution Ph ◽  
Gel Technique ◽  
Dta Curves ◽  
Oxygen Concentrations

Sifat dielektrik serbuk BaTiO3 yang disediakan melalui kaedah akues pada suhu rendah telah dikaji menggunakan kaedah spektroskopi impedans apabila didedahkan terhadap tahap oksigen yang berbeza. Untuk mengatasi masalah kebolehlarutan Ba dan Ti yang berbeza, nisbah sebatian Ba yang ditambah lebih tinggi daripada nisbah stoikiometri (tambahan 10%) dan nilai pH larutan yang tinggi (pH~13) diperlukan. Ujian XRD dan TGDTA menunjukkan BaTiO3 yang hampir tulen dapat disintesis melalui kaedah ini. Suhu pengkalsinan yang lebih tinggi menghasilkan darjah penghabluran bahan yang lebih tinggi. Kajian dielektrik menunjukkan bahan yang dihasilkan mengandungi lebih daripada satu elemen keelektrikan antaranya teras berkerintangan rendah, sempadan butiran berkapasitan tinggi dan suatu elemen pukal feroelektrik. Setelah didedahkan terhadap tahap oksigen yang lebih tinggi, nilai kerintangan sampel bertambah, yang mungkin disebabkan stoikiometri oksigen pada sampel yang diuji. Peningkatan dalam nilai kapasitan daripada sempadan butiran adalah lebih ketara jika dibandingkan dengan peningkatan unsur feroelektrik pukal. Kata kunci: Kaedah sol-gel, sintesis kimia, sifat dielektrik, BaTiO3 The dielectric properties of BaTiO3 powders prepared by a low temperature aqueous route when exposed to different oxygen concentrations have been studied by means of impedance spectroscopy. Due to the differences of solubility of Ba and Ti in aqueous solutions, deviations from stoichiometric ratios (a 10% excess) and higher solution pH (pH~13) were necessary. XRD traces and TG-DTA curves show the formation of nearly phase-pure BaTiO3 with higher calcinations temperatures promoting greater crystallinities. Dielectric measurements using impedance spectroscopy show the samples to consist of more than one electrical element including a low resistivity core, a high capacitance grain boundary and a ferroelectric bulk component. Exposing the samples to different oxygen concentrations caused a slight increase in resistivities with increasing oxygen concentration, which was attributed to the oxygen stoichiometry. A greater increase in the capacitance of the grain boundary component was also observed compared to the ferroelectric bulk. Key words: Sol-gel processes, chemical processes, dielectric properties, BaTiO3

scholarly journals Dielectric properties and leakage current of MgO/(Ba0.8Sr0.2)TiO3 heterostructured films prepared by sol-gel technique

2006 ◽  
Vol 55 (4) ◽  
pp. 2069
Author(s):  
Jia Jian-Feng ◽  
Huang Kai ◽  
Pan Qing-Tao ◽  
Li Shi-Guo ◽  
He De-Yan
Keyword(s):  
Dielectric Properties ◽  
Leakage Current ◽  
Sol Gel ◽  
Gel Technique

scholarly journals Separating bulk from grain boundary Li ion conductivity in the sol–gel prepared solid electrolyte Li1.5Al0.5Ti1.5(PO4)3

2015 ◽  
Vol 3 (42) ◽  
pp. 21343-21350 ◽  
Author(s):  
Stefan Breuer ◽  
Denise Prutsch ◽  
Qianli Ma ◽  
Viktor Epp ◽  
Florian Preishuber-Pflügl ◽  
...  
Keyword(s):  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Ion Transport ◽  
Solid Electrolyte ◽  
Transport Properties ◽  
Low Temperatures ◽  
Sol Gel ◽  
Ion Conductivity ◽  
Li Ion ◽  
Ceramic Electrolytes

Impedance spectroscopy measurements down to very low temperatures allowed for resolving bulk ion transport properties in highly conducting ceramic electrolytes.

Phase transformation and characterization of TiO2 and ZrO2 addition in the Li2O–Al2O3-SiO2 gels

1996 ◽  
Vol 11 (10) ◽  
pp. 2611-2615 ◽  
Author(s):  
Ming-Hong Lin ◽  
Moo-Chin Wang
Keyword(s):  
Phase Transformation ◽  
Sol Gel ◽  
Peak Position ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
Ceramic Powders ◽  
Higher Temperature ◽  
Gel Technique ◽  
Dta Curves

Glass-ceramic powders with a composition of Li2O · Al2O3 · 4SiO2 (LAS) have been synthesized by the sol-gel technique using LiOCH3, Al(OC2H5)3, Si(OC2H5)4, Ti(OC2H5)4, and Zr(OC2H5)4 as starting materials and the phase transformation behavior during calcination has been investigated. Differential thermal analysis (DTA), x-ray diffraction (XRD), and scanning electron microscopy (SEM) were utilized to determine the thermal behavior of the gels. Considering the LAS gels with 6.0 wt. % TiO2 and various wt. % ZrO2 content, and peak position of the β-spodumene phase formation in DTA curves was shifted to a higher temperature when the ZrO2 content was increased. The activation energy of β-spodumene crystallization was 283.8 kcal/mol for LAS gels with 6.0 wt. % TiO2 and 2.0 wt. % ZrO2. Unlike foregoing studies for LAS gels, during calcination of the dried LASTZ gels from 800 °C to 1200 °C neither β-eucryptite nor γ-spodumene was noted to be present. The crystallized phases comprised of β-spodumenes as the major phase and rutile (TiO2) together with zirconia (ZrO2) are precipitated as minor phases.

Dielectric Properties of Sol - Gel Silica Glasses

1986 ◽  
Vol 72 ◽  
Author(s):  
G. V. Chandrashekhar ◽  
M. W. Shafer
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Elemental Carbon ◽  
Sol Gel ◽  
Fused Silica ◽  
Dielectric Constants ◽  
Low Dielectric Constant ◽  
Silica Glasses ◽  
Low Dielectric ◽  
Gel Technique

AbstractDielectric properties have been measured for a series of porous and fully densified silica glasses, prepared by the sol-gel technique starting from Si-methoxide or Si-fume. The results for the partially densified glasses do not show any preferred orientation for porosity. When fully densified (˜2.25 gms/cc) without any prior treatment of the gels, they have dielectric constants of ≥ 6.5 and loss factors of 0.002 at 1 MHz, compared to values of 3.8 and <0.001 for commercial fused silica. There is no corresponding anomaly in the d.c. resistivity. Elemental carbon present to the extent of 400–500 ppm is likely to be the main cause for this enhanced dielectric constant. Extensive cleaning of the gels prior to densification to remove this carbon were not completely successful pointing to the difficulty in preparing high purity, low dielectric constant glasses via the organic sol-gel route at least in the bulk form.

Dielectric Properties of Mn, Co, and Ni-Doped LaSrFeO3 Films with Different Annealing Atmosphere

2015 ◽  
Vol 740 ◽  
pp. 28-31
Author(s):  
Yang Lu Hou ◽  
Xing Hua Fu ◽  
Wen Hong Tao ◽  
Hong Di Xue
Keyword(s):  
Thin Films ◽  
Dielectric Properties ◽  
Perovskite Phase ◽  
Sol Gel ◽  
Film Surface ◽  
Annealing Atmosphere ◽  
Single Perovskite Phase ◽  
Gel Technique

Mn, Co, and Ni-doped La0.5Sr0.5FeO3 thin films were prepared by the sol-gel technique with different annesling atmosphere. The structure and dielectric properties of the films were researched by XRD, SEM and Agilent. The study found that LSF-Mn (Co, Ni) films under the argon annealing atmosphere were have optimal dielectric properties. And Mn, Co, Ni elements are integrated into La0.5Sr0.5FeO3 lattices with the single perovskite phase. And uniform grain was distribution on the film surface.

Electrical/Dielectric Properties of Nanocrystalline Cerium Oxide

1996 ◽  
Vol 457 ◽  
Author(s):  
Jin-Ha Hwang ◽  
Thomas O. Mason ◽  
Edward J. Garboczi
Keyword(s):  
Dielectric Properties ◽  
Impedance Spectroscopy ◽  
Grain Boundary ◽  
Transport Properties ◽  
Cerium Oxide ◽  
High Resistance ◽  
Current Flow ◽  
Impedance Spectra ◽  
Electrode Interface ◽  
Microcrystalline Material

ABSTRACTElectrical/dielectric properties of nanocrystalline cerium oxide have been studied using impedance spectroscopy, thermopower, and DC 4-point conductivity. The combined techniques identified the effect of poor electroding on impedance spectra. Incomplete contact between the specimen and the electrode induces an additional arc in the impedance spectra. The additional high resistance feature results from the geometric constriction of current flow at the specimen/electrode interface and can be misinterpreted as a grain boundary response. The defect chemistry, nonstoichiometry, and transport properties were investigated in nanoscale ceria and compared with those of microcrystalline material.

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