Structural, Electrical and Dielectric Properties of Uranium Doped Barium Titanate

2006 ◽  
Vol 514-516 ◽  
pp. 1269-1273
Author(s):  
Cornel Miclea ◽  
Constantin Tanasoiu ◽  
Corneliu Florin Miclea ◽  
Anca Gheorghiu
Keyword(s):  
Dielectric Constant ◽  
Electrical Resistivity ◽  
Barium Titanate ◽  
Mixed Oxides ◽  
Raw Materials ◽  
Uranium Content ◽  
Sudden Increase ◽  
Sharp Maximum ◽  
Order Of Magnitude ◽  
Titanate Ceramics

The influence of uranium doping up to 2 at. % on grain size, electrical resistivity and dielectric constant of barium titanate ceramics has been investigated. The samples were prepared by the conventional ceramic technique using pure raw materials. The mixed oxides were calcined at 1100 oC. The pressed pellets were sintered at temperatures between 13001500 oC in controlled atmosphere of argon and oxygen. The electrical resistivity drastically decreased, from 109 to 103 cm, with increasing uranium content up to 1.5 at. % and increased thereafter to about 107 cm, for 2 at. % U. The dielectric constant slightly increased with increasing U-content, up to about 1 at. % U and then shows a sudden increase with about two orders of magnitude, having a sharp maximum at 1.5 at. % U, when sintered in argon atmosphere compared to only half an order of magnitude when sintered in oxygen atmosphere. The results are discussed in terms of the possible A and B sites occupied by uranium as well as the boundary layer enriched with vacancies.

Preparation of Potassium Niobate–Barium Titanate Ceramics Using Well-Dispersed Nanoparticles and their Dielectric Properties

2011 ◽  
Vol 485 ◽  
pp. 39-42 ◽  
Author(s):  
Kenta Yamashita ◽  
Shigehito Shimizu ◽  
Ichiro Fujii ◽  
Kouichi Nakashima ◽  
Nobuhiro Kumada ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Potassium Niobate ◽  
Conventional Sintering ◽  
Titanate Ceramics ◽  
Sintering Method

ANbO3– BaTiO3(A=K, Na, or K0.5Na0.5) system ceramics were prepared using a conventional sintering method, and their dielectric properties were investigated. It was found that the dielectric constant of KNbO3-BaTiO3and (K0.5Na0.5) NbO3- BaTiO3system ceramics did not strongly depend on temperature between 20 and 400 °C, making them useful for capacitor application.

Grain Size Dependence of the Microstructure and Dielectric Properties of Potassium Niobate-Barium Titanate Ceramics

2013 ◽  
Vol 566 ◽  
pp. 34-37
Author(s):  
Kenta Yamashita ◽  
Ichiro Fujii ◽  
Kouichi Nakashima ◽  
Nobuhiro Kumada ◽  
Yoshihiro Kuroiwa ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Size Dependence ◽  
Potassium Niobate ◽  
Titanate Ceramics

In this study, 0.8 KNbO3(KN) -0.2 BaTiO3(BT) ceramics were prepared using KN powder with the diameter of 100 nm and BT powders with the diameter of 100, 300, or 500 nm. The relative densities were more than 96 % of the theoretical densities of the samples. The dielectric constant of the samples was temperature-stable at temperatures between-50 and 300 °C and it was found that the dielectric constant of the 0.8KN-0.2BT ceramics increased as the BT diameter increased.

Broadband Dielectric Spectroscopy Analysis of Dielectric Properties of Barium Titanate Ceramics

2013 ◽  
Vol 744 ◽  
pp. 323-328 ◽  
Author(s):  
Jie Yang ◽  
Xiang Yun Deng ◽  
Jian Bao Li ◽  
Qiang Cai ◽  
Hai Tao Zhang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Barium Titanate ◽  
Relaxation Model ◽  
Debye Relaxation ◽  
Broadband Dielectric Spectroscopy ◽  
Function Fitting ◽  
Loss Experience ◽  
Titanate Ceramics

The complex dielectric behaviors of ferroelectric barium titanate (BT) ceramics were investigated. The dielectric properties were studied as a function of temperature and frequency using broadband dielectric spectrometer. The results show that the maximum value of dielectric constant occurs at 500nm BT ceramics, which is approximately 7,500; the dielectric loss is lower than 0.03 with the temperature varying from 225 K to 450 K. Dielectric constant and dielectric loss experience three dielectric peaks corresponding to rhombohedral to orthorhombic, tetragonal and cubic transitions. With the frequency ranges from 1 MHz to 1 GHz, the dielectric relaxation is apparently present. The relaxation process obeys Cole-Cole relaxation model at high temperature and conforms to Debye relaxation model when the temperature far lower than Curie temperature. The relaxation time is the order magnitude of ~10-9s obtained by Havriliak-Negami function fitting, which is very consistent with theoretical calculation.

scholarly journals Dependence of the dielectric properties of barium titanate ceramics and a composite based on it on the sintering temperature

2021 ◽  
Vol 24 (1) ◽  
pp. 40-47
Author(s):  
O. V. Malyshkina ◽  
A. I. Ivanova ◽  
Gr. S. Shishkov ◽  
A. A. Martyanov
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Barium Ferrite ◽  
Sintering Temperature ◽  
Pyroelectric Coefficient ◽  
Ceramic Samples ◽  
Barium Titanate Ceramic ◽  
Titanate Ceramics ◽  
Composite Samples

In this paper, we compare the structure and dielectric properties of the samples of barium titanate ceramics that have been sintered at temperatures of 1100, 1150, 1200, 1250 and 1350 °C and dielectric characteristics of the samples of barium titanate (80 vol.%) — barium ferrite (20 vol.%). It is shown that only samples sintered at the temperature of 1250 and 1350 °C have polarization sufficient for the existence of the piezoelectric effect. For the same samples, the pyroelectric coefficient and reversal polarization significantly exceed those for samples sintered at lower temperatures. Analysis of the samples structure confirmed the dependence of the dielectric properties of the barium titanate ceramics on the grain size and, as a consequence, on the sintering temperature. Based on the studies carried out, the optimal temperature (1250 °С) for obtaining composite samples of barium titanate (80 vol.%) — barium ferrite (20 vol.%) was selected. The temperature dependence of the dielectric constant for the composite samples based on barium ferrite — barium titanate with a sintering temperature of 1250 °C is similar to the dependence for the BaTiO3 ceramic samples sintered at 1350 °C. At room temperatures, the permittivity of the composite samples is also significantly higher than that of the barium titanate ceramic samples obtained at the same sintering temperatures. The addition of barium ferrite to the barium titanate not only increased the permittivity of the composite, but also led to a diffusing of the ferroelectric phase transition and a shift in the temperature of the maximum of the dielectric constant by 10 degrees towards high temperatures.

Investigation of Structural, Dielectric and Electrical Properties of Barium Titanate Ceramics Co-Doped with Bismuth and Yttrium

2019 ◽  
Vol 07 (03n04) ◽  
pp. 1950006
Author(s):  
Suravi Islam ◽  
Syed Abdus Satter ◽  
Nazia Khatun ◽  
Mohammad Sajjad Hossain ◽  
Syed Farid Uddin Farhad ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Doping Concentration ◽  
Solid State Reaction Method ◽  
Cubic Phase ◽  
Dc Resistivity ◽  
Maximum Dielectric Constant ◽  
Sem Micrograph ◽  
Titanate Ceramics ◽  
Co Doped

Bismuth and Yttrium co-doped Barium Titanate (BaTiO3) ceramics with the general formula (Ba[Formula: see text]BiX) (YxTi[Formula: see text]) O3 (where [Formula: see text], 0.01, 0.03, 0.05) have been synthesized at 1300∘C for 3[Formula: see text]h by the standard solid-state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Impedance Analyzer. Temperature-dependent dielectric properties of the samples were also measured. The XRD result revealed perovskite structure for un-doped and co-doped BaTiO3 with tetragonal phase. However, with increasing doping concentration, a Pseudo cubic phase occurs also confirmed by the twin peaks (002) and (200) of XRD pattern. From SEM micrograph, submicron size particles were observed for all synthesized BaTiO3 samples and exhibit a narrow size distribution with quiet uniform morphology. The crystalline size for un-doped BaTiO3 found was 24.26[Formula: see text]nm, the size decreases (minimum 19.59[Formula: see text]nm for [Formula: see text]) for all compositions of co-doped BaTiO3. Dielectric constant values were apparently high and direct current (DC) resistivity follows a decreasing trend at higher doping concentration. The sample doped with [Formula: see text] shows minimum DC resistivity and maximum dielectric constant among the samples investigated.

Investigation on the Correlation between Structural and Electrical Properties of Lanthanum Doped Barium Titanate Ceramics

2016 ◽  
Vol 860 ◽  
pp. 99-104
Author(s):  
Masum Billah ◽  
Md Miftaur Rahman
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Barium Titanate ◽  
Curie Temperature ◽  
Raw Materials ◽  
Structure Property ◽  
Structural And Electrical Properties ◽  
Doped Barium Titanate ◽  
Titanate Ceramics ◽  
Relationship Of

The structure-property relationship of 0.3, 0.5 and 0.7mole% lanthanum (La2O3) doped Barium titanate (BaTiO3) ceramics prepared by solid state sintering under different sintering conditions were investigated in this research. The raw materials were La2O3 (grain size=~80nm) and BaTiO3 (grain size=100nm) powders. Field Emission Scanning Electron Microscope (FE-SEM) was used to examine grain size and surface morphology of sintered pellets & X-Ray Diffraction analysis was conducted to identify crystal structure. The results showed significantly improved grain size and electrical properties of BaTiO3 for 0.5 mole% La2O3 with desired grain size (0.8-1.3μm), high densification (>90% theoretical density) and stable dielectric constant (12700) at room temperature (f=100Hz) by lowering curie temperature around 30oC by sintering at 1300oC for 8 hrs. A gradual deterioration follows with increased doping concentration. So the research revealed that proper La3+ concentration can inhibit grain size and lower Curie temperature hence significantly improving the electrical properties of BaTiO3 ceramics.

Characteristics of Porous Sb-Doped Barium Titanate Ceramics Fabricated by Adding Graphite

2015 ◽  
Vol 1107 ◽  
pp. 9-13
Author(s):  
Nurafizalwani Ayub ◽  
Ramli Omar ◽  
Mohamad Deraman ◽  
Ibrahim Abutalib ◽  
Zalita Zainuddin ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrical Resistivity ◽  
Barium Titanate ◽  
Grain Boundaries ◽  
Barrier Height ◽  
Perovskite Structure ◽  
Density Structure ◽  
Exothermic Reactions ◽  
Doped Barium Titanate ◽  
Titanate Ceramics

Porous Sb-doped barium titanate (Sb-BaTiO3) ceramics were fabricated by adding various amounts of graphite powders. The density, structure, microstructure, porosity and electrical resistivity of the porous Sb-BaTiO3 ceramics produced without and with graphite were investigated. All the sintered ceramics showed a tetragonal perovskite structure, irrespective of the amount of graphite added. The porosity of the ceramics increased and the grain size decreased with increasing graphite addition which mainly due to the exothermic reactions of the graphite and oxygen molecules in the ceramics. The prepared porous Sb-BaTiO3 ceramics exhibit PTCR behavior where the PTCR jump of the ceramics with graphite was about 103 which is higher than that of the ceramics without graphite. The increasing in the PTCR jump with increasing graphite addition was attributed mainly due to the increase in the electrical barrier height of grain boundaries and the porosity. It was found that the graphite is an effective pore forming agent for fabricating porous BaTiO3-based ceramics.

DC AND AC ELECTRICAL PROPERTIES OF PTC BARIUM TITANATE CERAMICS

1990 ◽  
Vol 51 (C1) ◽  
pp. C1-979-C1-984
Author(s):  
S. HISHITA ◽  
J. F. BAUMARD ◽  
P. ABELARD
Keyword(s):  
Electrical Properties ◽  
Barium Titanate ◽  
Ac Electrical Properties ◽  
Titanate Ceramics
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