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 and Magnetic Properties of Sintered Cobalt Ferrite Derived from Nanocrystalline Powders

2012 ◽  
Vol 476-478 ◽  
pp. 726-729 ◽  
Author(s):  
Liang Neng Wu ◽  
Li Zhen Jiang ◽  
Fang Yu Hong
Keyword(s):  
Dielectric Constant ◽  
Magnetic Properties ◽  
Hysteresis Loop ◽  
Loss Tangent ◽  
Room Temperature ◽  
Cobalt Ferrite ◽  
Relative Dielectric Constant ◽  
Nanocrystalline Powders ◽  
Magnetic Characteristics ◽  
Dielectric Constant And Loss

A kind of Cobalt ferrite ceramics were successfully prepared by using nanocrystalline powders synthesized by citrate gel method. The relative dielectric constant and loss tangent of the ceramic as a function of frequency (100 Hz - 1 MHz) was investigated at room temperature. Both of them decrease with increase in frequency showing dispersion. Hysteresis loop magnetization was measured and the ceramic show good magnetic characteristics at room temperature.

The influence of direct current bias on the initial aging of a doped lead magnesium niobate ceramic

1998 ◽  
Vol 13 (3) ◽  
pp. 675-679 ◽  
Author(s):  
Y. Wang ◽  
Y. C. Chan ◽  
Z. L. Gui ◽  
L. T. Li
Keyword(s):  
Dielectric Constant ◽  
Direct Current ◽  
Loss Tangent ◽  
Lead Magnesium Niobate ◽  
Dielectric Parameters ◽  
Magnesium Niobate ◽  
Dielectric Constant And Loss ◽  
Wide Range ◽  
Lead Magnesium ◽  
Dc Bias

The initial dielectric aging behaviors of a Mg and Mn doped lead magnesium niobate ceramic were investigated over a wide range of direct current (dc) bias. Both the dielectric constant-log(time) and the loss tangent-log(time) were regressed in terms of a linear relationship. The dc bias is found to have a strong influence on the dielectric parameters at the start of aging and to suppress the aging of dielectric constant and loss tangent. The frequency dependence of the dielectric aging is also evidently affected by the dc bias.

scholarly journals AC CONDUCTIVITY AND DIELECTRIC STUDIES OF POLYPYRROLE-PAPAIN COMPOSITE

2019 ◽  
Vol 7 (8) ◽  
pp. 332-338
Author(s):  
Pandey Munish ◽  
Badlani Richa
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
In Situ Polymerization ◽  
Weight Percent ◽  
Oxidizing Agent ◽  
Dielectric Studies ◽  
Dielectric Constant And Loss ◽  
Lcr Meter ◽  
Room Temperature Dielectric Constant

Enzyme doped polypyrrole polymer were synthesized by in situ polymerization where ferric chloride works as an oxidizing agent. The different weight percent of papain was added at the time of polymerization. The polypyrrole-papain composite of various composition was analyzed for its dielectric and a. c. conductivity by using LCR meter at room temperature. Dielectric constant and loss decreases, with escalation in frequency. The variation in dielectric constant and dielectric loss was also noted with change in papain percentage in pyrrole.

THE DIELECTRIC PROPERTIES OF SELECTED BASALTS

Geophysics ◽  
1973 ◽  
Vol 38 (1) ◽  
pp. 135-139 ◽  
Author(s):  
W. Hansen ◽  
W. R. Sill ◽  
S. H. Ward
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Loss Tangent ◽  
Room Temperature ◽  
Frequency Dispersion ◽  
Nitrogen Atmosphere ◽  
Frequency Range ◽  
Dielectric Constant And Loss ◽  
Identical Composition ◽  
Titanium Compounds

Basaltic samples of known chemical composition were measured for dielectric constant and loss tangent in the frequency range 100 hz to 50 Mhz. All samples were prepared and measured by a contact substitution method in a dry nitrogen atmosphere at room temperature. The measurements indicated a general spectrum of dielectric constant with a range of 10–65 at 100 hz to 7–15 at 50 Mhz with frequency dispersion observed to be minimal above 1 Mhz. The loss tangent decreases from a range .2–.9 at 100 hz to a range .02–.15 at 100 khz. A finer‐grained sample was observed to have higher dielectric properties below 1 Mhz than a coarser‐grained sample of identical composition. A qualitative and subsequent quantitative study of possible compositional effects indicated that iron‐titanium compounds may be responsible for observed variations in the dielectric spectra of typical basalts.

Phase Transition and Dielectric Tunability of Chemical Solution Deposited (Pb0.35Sr0.65)(Zr0.5Ti0.5)O3 Thin Films on Pt/ZrO2/SiO2/Si Substrates

2007 ◽  
Vol 1034 ◽  
Author(s):  
Naba K Karan ◽  
Marilin Perez ◽  
Jose Saavedra ◽  
Dillip K Pradhan ◽  
Reji Thomas ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Seed Layer ◽  
Room Temperature ◽  
Single Phase ◽  
Frequency Dispersion ◽  
Chemical Solution ◽  
Solution Deposition ◽  
Si Substrates ◽  
Dielectric Constant And Loss

Abstract(Pb0.35Sr0.65)(Zr0.5Ti0.5)O3 thin films were grown on Pt/ZrO2/SiO2/Si substrates by chemical solution deposition. As-deposited (pyrolysed at 500°C) films were amorphous and single phase films were obtained at temperature as low as 550°C with a 30 nm SrTiO3 seed layer. Dielectric constant and loss tangent at room temperature were 210 and 0.022, respectively at 100 kHz for the film annealed at 700°C. Frequency dispersion of the dielectric properties was low. The phase transition temperature (ferroelectric to paraelectric) was well below the room temperature and was around 220 K. The room temperature tunability and the k-factor at 500 kV/cm was around 45% and 16, respectively.

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