Preparation of Ferroelectric BaTiO3 Films by Electrophoretic Deposition Technique

2007 ◽  
Vol 336-338 ◽  
pp. 87-90
Author(s):  
Ya Lu Ma ◽  
Yu Zhang ◽  
Hong Long Zhu
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Electrophoretic Deposition ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Ferroelectric Films ◽  
Final Annealing ◽  
Xrd Pattern ◽  
Uniform Microstructure ◽  
Room Temperature Dielectric Constant

Barium titanate ferroelectric films on Pt substrates were fabricated by electrophoretic deposition (EPD) technique. The barium titanate films sintered at different temperature (600°C, 900°C, 1050°C, 1150°C, 1200°C) for 2h, which were prepared via repeated EPD-sintering route 2~3 times were sufficiently dense and had uniform microstructure. The XRD pattern and SEM microphotography have been measured in order to investigate the effects of the final annealing temperature on the phase compositions and microstructure of the film. The experiment results showed that barium titanate films were crystallized into the tetragonal phase at 1050°C and above. The room temperature dielectric constant (ε) and loss tangent (tanδ) at 1kHz were respectively determined for different samples sintered at 600°C, 900°C, 1050°C, 1150°C and 1200°C. Both ε and tanδ showed anomaly peaks at 125°C. The results showed that typical BaTiO3 films sintered at 1050°C having higher dielectric constant (ε=2300) and lower dielectric loss (tanδ=0.02). The room temperature remanant polarization (Pr) and coercive field (EC) were found to be 1.9μC/cm2 and 35kV/cm, respectively.

DIELECTRIC PROPERTIES OF CHEMICALLY SYNTHESIZED PbTiO3 NANOCRYSTALS SUITABLE FOR HIGH FREQUENCY DEVICES

2010 ◽  
Vol 24 (23) ◽  
pp. 4547-4554
Author(s):  
K. C. VERMA ◽  
M. SINGH ◽  
N. THAKUR ◽  
N. S. NEGI
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Room Temperature ◽  
Pt Nanoparticles ◽  
X Ray Diffraction ◽  
Chemical Route ◽  
Xrd Pattern ◽  
High Frequency Devices ◽  
Room Temperature Dielectric Constant ◽  
Transmission Scanning Electron Microscopy

PbTiO 3 (PT) nanoparticles have been prepared by chemical route using polyvinyl alcohol (PVA) as an efficient surfactant. The effect of PVA to reduce the particle's sizes of PT has been observed. X-ray diffraction (XRD) pattern shows that the PT nanoparticles are tetragonal with distortion ratio, c/a ~1.061. The average particle's size calculated from XRD and transmission/scanning electron microscopy is ~24 nm for PT powder sintered at 700°C. The nanostructured grains were also observed in PT pellet sintered at 1000°C. The dielectric properties of PT pellet have been measured from room temperature to 200°C and in the frequency range of 0.075 to 10 MHz. The values of room temperature dielectric constant and tanδ are 117 and 0.05 respectively, measured at 0.5 MHz. It is found that the dielectric constant of PT nanoparticles can be controlled up to higher frequency region of 5 MHz.

Effect of Sintering Time on Dielectric Properties of Barium Titanate and Nb Doped Barium Titanate

2016 ◽  
Vol 860 ◽  
pp. 129-133 ◽  
Author(s):  
M.K. Rahman ◽  
M.F. Hossain ◽  
Kazi Mohammad Shorowordi ◽  
M.A. Matin
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Barium Titanate ◽  
Room Temperature ◽  
Niobium Oxide ◽  
Dielectric Material ◽  
Multilayer Ceramic Capacitors ◽  
Sintering Time ◽  
High K ◽  
Room Temperature Dielectric Constant

Barium titanate (BaTiO3) with its perovskite structure is a promising dielectric material for many applications such as transducers, actuators, high-k dielectrics and multilayer ceramic capacitors (MLCC). In this study, we have investigated the effect of sintering time on dielectric properties of BaTiO3 and Nb-doped BaTiO3. BaTiO3 was doped with 0.3 mol % niobium oxide (Nb2O5). At first, nanosized pure BaTiO3 and Nb2O5 doped BaTiO3 were milled, dried and pressed into pellets to prepare green samples. Then, the samples were sintered at 1275°C for different time periods ranging from 2 to 5 hrs. Single stage sintering was adopted for the densification of prepared samples. Microstructure of the sintered samples was investigated employing Field-emission scanning electron microscope (FESEM). Dielectric properties of the samples were measured using an impedance analyzer. Finally, a correlation was established between the dielectric properties of the sintered samples and their microstructure. Nb has shown to provide strong inhibiting effect after sintering the samples in the range of 2 to 5 hours at 1275°C thereby, resulted in higher dielectric properties of doped BaTiO3 ceramics compared to that of pure BaTiO3. The best room temperature dielectric constant of 7200 was obtained for Nb doped BaTiO3 sintered at 1275°C for five hours. Such improved dielectric constant is attributed to the optimum grain size of about 1 micron at this sintering temperature.

scholarly journals Synthesis and electrical characterization of Ca2Nd4Ti6O20 ceramics

2016 ◽  
Vol 34 (1) ◽  
pp. 164-168
Author(s):  
Raz Muhammad ◽  
Muhammad Uzair ◽  
M. Javid Iqbal ◽  
M. Jawad Khan ◽  
Yaseen Iqbal ◽  
...  
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Room Temperature ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Sintered Sample ◽  
First Time ◽  
Alkoxide Precursors ◽  
Room Temperature Dielectric Constant

AbstractCa2Nd4Ti6O20, a layered perov skite structured material was synthesized via a chemical (citrate sol-gel) route for the first time using nitrates and alkoxide precursors. Phase analysis of a sample sintered at 1625 °C revealed the formation of an orthorhombic (Pbn21) symmetry. The microstructure of the sample after sintering comprised rod-shaped grains of a size of 1.5 to 6.5µm. The room temperature dielectric constant of the sintered sample was 38 at 100 kHz. The remnant polarization (Pr) and the coercive field (Ec) were about 400 μC/cm2 and 8.4 kV/cm, respectively. Impedance spectroscopy revealed that the capacitance (13.7 pF) and activation energy (1.39 eV) of the grain boundary was greater than the capacitance (5.7 pF) and activation energy (1.13 eV) of the grain.

scholarly journals The effects of additive on microstructure and electrical properties of batio3 ceramics

2004 ◽  
Vol 1 (3) ◽  
pp. 89-98 ◽  
Author(s):  
Vesna Paunovic ◽  
Ljiljana Zivkovic ◽  
Ljubomir Vracar ◽  
Vojislav Mitic ◽  
Miroslav Miljkovic
Keyword(s):  
Dielectric Constant ◽  
Curie Temperature ◽  
Room Temperature ◽  
Low Frequency ◽  
Dissipation Factor ◽  
The Other ◽  
Uniform Microstructure ◽  
Average Grain Size ◽  
Solid State Sintering ◽  
Curie Temperatures

In this paper comparative investigations of microstructure and dielectric properties of BaTiO3 ceramics doped with 1.0 wt% of Nb2O5, MnCO3 and CaZrO3 have been done. BaTiO3 samples were prepared using conventional method of solid state sintering at 13000C for two hours. Two distinguish micro structural regions can be observed in sample doped with Nb2O5. The first one, with a very small grained microstructure and the other one, with a rod like grains. In MnCO3 and CaZrO3 doped ceramics the uniform microstructure is formed with average grain size about 0.5- 2?m and 3-5?m respectively. The highest value of dielectric permittivity at room temperature and the greatest change of permittivity in function of temperature were observed in MnCO3/BaTiO3. In all investigated samples dielectric constant after initially large value at low frequency attains a constant value at f = 6kHz. A dissipation factor is independent of frequency greater than 10 kHz and, depending of systems, lies in the range from 0.035 to 0.25. At temperatures above Curie temperatures, the permittivity of all investigated samples follows a Curie- Weiss law. A slight shift of Curie temperature to the lower temperatures, in respect of Curie temperature for undoped BaTiO3, was observed in all investigated samples.

The Effect of Hydrogen/ Deuterium Introduction on Photoluminescence of 3C-SiC Crystals

1998 ◽  
Vol 513 ◽  
Author(s):  
B. K. Lee ◽  
A. J. Steckl ◽  
J. M. Zavada ◽  
R. G. Wilson
Keyword(s):  
Room Temperature ◽  
Annealing Temperature ◽  
Laser Excitation ◽  
Peak Wavelength ◽  
Final Annealing ◽  
Increasing Trend ◽  
Area Increase ◽  
Hydrogen Deuterium ◽  
Pl Intensity ◽  
Post Implantation

ABSTRACTThe effect of the incorporation and annealing of deuterium in 3C-SiC on its photoluninescence is reported. A 3C-SiC crystal has been implanted with 100 keV deuterium and subsequently annealed at temperatures between 1015 °C and 1220 °C for 1 to 5 minutes. SIMS depth profiles indicate hydrogen is strongly trapped by defects generated through ion bombardment, but a gradual damage repairing occurs during annealing. Photoluminescence was measured with 488 nm Ar laser excitation for sample temperatures from 89 K to 400 K. The PL peak wavelength of 540 nm at room temperature has shifted to 538 nm at 89 K. The peak PL intensity decreases with measurement temperature while its full width at half maximum (FWHM) exhibits an increasing trend. PL data were taken at five annealing stages. The post-implantation peak PL intensity and its integrated area increase initially with annealing temperature and time. After the final annealing at 1218 °C for 2 minute, PL intensity and its integrated area exhibit a decrease in level.

Dielectric Properties of Sintered AIN

1989 ◽  
Vol 167 ◽  
Author(s):  
R. D. Harris ◽  
R. C. Enck ◽  
J. L. Fields
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Room Temperature ◽  
Dc Resistivity ◽  
Thermally Activated ◽  
Exponential Factors ◽  
Ac Electrical Properties ◽  
Different Sources ◽  
Room Temperature Dielectric Constant ◽  
Product Literature

AbstractWe have initiated a study of the ac electrical properties (dielectric constant and dielectric loss) and the dc resistivity of sintered AIN. For this study, we have used samples purchased commercially as well as samples made by the Carborundum Company, a member of the BP Group. Variations are observed in the room temperature dielectric constant for AIN substrates obtained from different sources. The source-to-source range is from 8.5 to 8.7. This range is lower than the 8.8 to 9.2 that is generally reported in the product literature. Similar source-tosource variations in the room temperature dielectric loss are observed. All of the samples show thermally activated behavior in the dc resistivity. The activation energy observed for all of the samples is similar, EA ∼0.47 eV; however, different pre-exponential factors are apparent. As a result, there are large variations in the measured room temperature resistivities for samples from different sources.

Dielectric Properties of Pulsed Excimer Laser Ablated BaBi2Nb2O9 Thin Films

2002 ◽  
Vol 748 ◽  
Author(s):  
Apurba Laha ◽  
S. B. Krupanidhi ◽  
S. Saha
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Dielectric Constant ◽  
Temperature Dependence ◽  
Loss Tangent ◽  
Dielectric Response ◽  
Room Temperature ◽  
Dielectric Constant And Loss ◽  
Wide Range ◽  
Room Temperature Dielectric Constant

ABSTRACTThe dielectric response of BaBi2Nb2O9 (BBN) thin films has been studied as a function of frequency over a wide range of temperatures. Both dielectric constant and loss tangent of BBN thin films showed a ‘power law’ dependence with frequency, which was analyzed using the Jonscher's universal dielectric response model. Theoretical fits were utilized to compare the experimental results and also to estimate the value of temperature dependence parameters such as n(T) and a(T) used in the Jonscher's model. The room temperature dielectric constant (ε') of the BBN thin films was 214 with a loss tangent (tanδ) of 0.04 at a frequency of 100 kHz. The films exhibited the second order dielectric phase transition from ferroelectric to paraelectric state at a temperature of 220 °C. The nature of phase transition was confirmed from the temperature dependence of dielectric constant and sponteneous polarization,respectively. The calculated Currie constant for BBN thin films was 4 × 105°C.

DIELECTRIC STUDIES OF SAMARIUM MODIFIED (Pb)(Zr, Ti, Fe, Nb)O3 CERAMIC SYSTEM

2009 ◽  
Vol 23 (11) ◽  
pp. 1437-1442 ◽  
Author(s):  
PRATIBHA SINGH ◽  
SANGEETA SINGH ◽  
J. K. JUNEJA ◽  
CHANDRA PRAKASH ◽  
K. K. RAINA
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
Single Phase ◽  
Xrd Analysis ◽  
Solid State Reaction Method ◽  
Dielectric Studies ◽  
Dielectric Measurements ◽  
Ceramic System ◽  
Reaction Method ◽  
Room Temperature Dielectric Constant

Here we report the investigations on Sm -substituted PZTFN ( Pb 1-x Sm x Zr 0.588 Ti 0.392 Fe 0.01 Nb 0.01 O 3) (where x = 0, 0.02, 0.04, 0.06, 0.08, 0.10) polycrystalline solid solutions fabricated by solid-state reaction method. XRD analysis shows all the samples to be single phase with tetragonal structure. Dielectric measurements were carried out in the temperature range 30°C–400°C at different frequencies in the range 100 Hz to 100 kHz. From the temperature variation of dielectric constant (ε), Curie temperature (TC) was determined which was found to decrease with increasing x. The room temperature dielectric constant (ε RT ) initially increases with increasing x and then starts decreasing. Dielectric loss improves with Sm -doping.

Investigation of Low Temperature Sintering of Low Voltage Varistor Based on TiO2

2014 ◽  
Vol 852 ◽  
pp. 12-16 ◽  
Author(s):  
De Jun Lan ◽  
Shu Quan Wan
Keyword(s):  
Dielectric Constant ◽  
Low Temperature ◽  
Room Temperature ◽  
Low Voltage ◽  
Structural Characteristics ◽  
Nonlinear Coefficient ◽  
Xrd Analysis ◽  
Low Temperature Sintering ◽  
Powder Xrd Analysis ◽  
Room Temperature Dielectric Constant

Low temperature sintering of TiO2-base varistor was systematically investigated through doing with V2O5 and B-Si glass. Pellets prepared could be densely sintered from 1273 to 1473K. The highest relative density, 94.6%, was found in the sample sintered at 1433K. According to I-V plots of ceramic pellets, the nonlinear coefficient α and breakdown voltage V1mA were obtained and found to be α=2~5 and V1mA=15~30V. The room temperature dielectric constant was very large, high as to about 20000. Powder XRD analysis has shown the desirable macro-structural characteristics of these compacts.

Influence of sintering technique on the characteristics of Li–Co nanoferrites

2017 ◽  
Vol 31 (33) ◽  
pp. 1750314 ◽  
Author(s):  
Maisnam Victory ◽  
Mamata Maisnam ◽  
Sumitra Phanjoubam
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Constant ◽  
Room Temperature ◽  
Sol Gel ◽  
Conventional Technique ◽  
Vibrating Sample Magnetometer ◽  
Microstructural Properties ◽  
Room Temperature Dielectric Constant ◽  
Scanning Electron

Li–Co nanoferrites (Li[Formula: see text]Co[Formula: see text]Fe[Formula: see text]O4) with x = 0.00, 0.03, 0.06, 0.09, and 0.12, were synthesized by chemical sol–gel method. Two different sintering techniques viz. conventional technique (CT) and microwave technique (MT) were employed to heat treat the synthesized samples with an aim to study the effect of sintering technique on the properties of the nanoferrites. Structural and microstructural properties of the samples were investigated using XRD and scanning electron microscopy (SEM) technique, respectively. The variation of room temperature dielectric constant and dielectric loss were measured as a function of frequency in the range 100 Hz–1 MHz and the normal dispersive behavior was observed. Magnetic properties were investigated using Vibrating Sample Magnetometer (VSM), while Soohoo’s method was used to measure Curie temperature. The results obtained have been discussed in the paper.

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