Effect of SiO2 a
Effect
of SiO2 addition on the electrical properties of Ni-doped Cu-Cr
ferrites
El- Kony D.
Physics Department, Faculty
of Science ,Tanta University ,Tanta ,Egypt. [email protected]
Abstract: Ferrite
samples having the composition (Cu1-xNixCr FeO4; x
= 0.2, 0.4, 0.6 and 0.8) was prepared using the usual ceramic technique. Then composites
of these ferrites with SiO2 were prepared by mixing 25% weight
of SiO2 powder with 75% weight of each composition of the
ferrite powders. The dc conductivity and the dielectric properties of the
samples were investigated. The dielectric constant (ɛ′) and ac conductivity (σʹac)
were measured at different frequencies and temperatures. The variation of the
ac conductivity with temperature shows semiconducting behavior, whilst
with frequency it shows almost constant values over a wide range especially at
high temperatures and a slight increase with increasing frequency at lower
temperatures. This behavior indicates that the studied composites may be good
candidates for many applications. The dielectric constant shows some broad
peaks which shifts to higher frequencies with increasing the temperature. These
results are explained as due to the existence of two types of charge carriers
(n and P) in Cu containing ferrites. The algebraic sum of their contribution
to the polarization gives rise to those peaks. The results show that adding
silicon dioxide has reduced the conductivity significantly or in other words
increased the resistivity of the material, which improves the dielectric
properties of the system to be used in applications that requires very low
levels of eddy currents.
[El- Kony D.. Effect of SiO2 addition
on the electrical properties of Ni-doped Cu-Cr ferrites] Journal
of American Science 2012;8(10):697-705]. (ISSN: 1545-1003). http://www.jofamericanscience.org. 94
Key words: Dielectric Properties; DC Conductivity;
Soft Ferrites. Full Text 94
