%0 Journal Article
	%A A. Sedky and  E. El-Suheel
	%D 2012
	%J International Journal of Physical and Mathematical Sciences
	%B World Academy of Science, Engineering and Technology
	%I Open Science Index 65, 2012
	%T Nonlinear Conduction in Pure and Doped ZnO Varistors
	%U https://publications.waset.org/pdf/1787
	%V 65
	%X We report here structural, mechanical and I-V
characteristics of Zn1-xMxO ceramic samples with various x and M.
It is found that the considered dopants does not influence the wellknown
peaks related to wurtzite structure of ZnO ceramics, while the
shape and size of grains are clearly affected. Average crystalline
diameters, deduced from XRD are between 42 nm and 54 nm, which
are 70 times lower than those obtained from SEM micrographs.
Interestingly, the potential barrier could be formed by adding Cu up
to 0.20, and it is completely deformed by 0.025 Ni additions. The
breakdown field could be enhanced up to 4138 V/cm by 0.025 Cu
additions, followed by a decrease with further increase of Cu . On
the other hand a gradual decrease in VHN is reported for both
dopants and their values are higher in Ni samples as compared to Cu
samples. The electrical conductivity is generally improved by Ni,
while addition of Cu improved it only in the over doped region (≥
0.10). These results are discussed in terms of the difference of
valency and ferromagnetic ordering for both dopants as compared to
undoped sample.
	%P 496 - 502