scholarly journals Synthesis and Characterization of CaxSryBa1-x-yFe12-zLazO19 by Standard Ceramic Method

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Rohit K. Mahadule ◽  
Purushottam R. Arjunwadkar ◽  
Megha P. Mahabole

The polycrystalline compounds with chemical formula CaxSryBa1-x-yFe12-zLazO19 (CSBFLO) were synthesized via standard ceramic method. The chemical phase analysis was carried out by X-ray powder diffraction (XRD) method, which confirmed the formation of the magnetoplumbite phase belonging to ferrite structure. The frequency dependence of AC conductivity and dielectric constant was studied in the frequency range of 10 Hz to 2 MHz. The experimental results revealed that AC conductivity increases with increasing frequency, which is in agreement with Koop’s phenomenological theory. However, variation in dielectric constant required explanation in light of dielectric polarization. Magnetic characterization included studies of parameters such as Ms, Mr, Hc, and Tc, and results were explained via magnetic dilution and canting spin structure.

2013 ◽  
Vol 645 ◽  
pp. 56-59
Author(s):  
Shinde J. Tukaram ◽  
Gadkari B. Ashok ◽  
Vasambekar N. Pramod

Nickel–zinc ferrites with chemical formula Ni1-xZnxFe2O4 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) were prepared by oxalate co-precipitation method. The dielectric constant (ε') dielectric loss (tanδ) and AC conductivity (σac) of all the samples were determined at room temperature in the frequency range 20Hz -1MHz. The dielectric constant and dielectric loss are much smaller than those for samples prepared by ceramic method. The dielectric behaviour is attributed to the Maxwell–Wagner type interfacial polarization. AC conductivity of all the samples lies in the range 1.20×10-8 to 54.7×10-8 Ω-1cm-1. Low dielectric loss and high resistivity suggest the suitability of these ferrites for high frequency applications.


Author(s):  
A. Ege Engin ◽  
Abdemanaf Tambawala ◽  
Madhavan Swaminathan ◽  
Swapan Bhattacharya ◽  
Pranabes Pramanik ◽  
...  

1990 ◽  
Vol 180 ◽  
Author(s):  
G. Teowee ◽  
J.M. Boulton ◽  
H.H. Fox ◽  
A. Koussa ◽  
T. Gudgel ◽  
...  

ABSTRACTPolycerams are an emergent class of hybrid, multifunctional materials which combine the properties of organic and inorganic materials. Films have been prepared from silicon alkoxides and reactive, functionalized polymers such as triethoxysilyl modified polybutadiene (MPBD), (N-triethoxysilylpropyl)O polyethylene oxide urethane (MPEOU) and trimethoxysilylpropyl substituted polyethyleneimine (MPEI). Characterization of dielectric constant and tan δ of the films has been carried out over a range of frequency from 500 Hz to 100 kHz; and the results are used to consider the potential of Polycerams as dielectric materials.


2006 ◽  
Vol 20 (29) ◽  
pp. 1879-1882 ◽  
Author(s):  
CHANDRA PRAKASH ◽  
J. K. JUNEJA

In the present paper, we report the effect of Samarium substitution and Niobium doping on the properties of a PZT(52:48). The properties studied are: structural, dielectric and ferroelectric. The samples with chemical formula Pb 0.99 Sm 0.01 Zr 0.52 Ti 0.48 O 3 were prepared by solid-state dry ceramic method. Small amount (0.5 wt%) of Nb 2 O 5 was also added. X-ray diffraction (XRD) analysis showed formation of a single phase with tetragonal structure. Dielectric properties were studied as a function of temperature and frequency. Transition temperature, Tc, was determined from dielectric constant versus temperature plot. The material shows well-defined ferroelectric (PE) hysteresis loop.


2014 ◽  
Vol 04 (04) ◽  
pp. 1450035 ◽  
Author(s):  
Lin Zhang ◽  
Patrick Bass ◽  
Zhi-Min Dang ◽  
Z.-Y. Cheng

The equation ε eff ∝ (ϕc - ϕ)-s which shows the relationship between effective dielectric constant (εeff) and the filler concentration (φ), is widely used to determine the percolation behavior and obtain parameters, such as percolation threshold φc and the power constant s in conductor–dielectric composites (CDCs). Six different systems of CDCs were used to check the expression by fitting experimental results. It is found that the equation can fit the experimental results at any frequency. However, it is found that the fitting constants do not reflect the real percolation behavior of the composites. It is found that the dielectric constant is strongly dependent on the frequency, which is mainly due to the fact that the frequency dependence of the dielectric constant for the composites close to φc is almost independent of the matrix.


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