Abstract
Glass with composition 88SiO(2-6)Li(2)O-6Nb(2)O(5) (mol%) was
successfully prepared by the sol-gel technique. The dried and
translucent get was heat-treated at temperatures between 500 degrees C
and 800 degrees C. Lithium niobate crystallites, an important
ferroelectric material, were detected in the gel derived glass-ceramics
heat-treated above 650 degrees C. The de electrical conductivity
(sigma(dc)) temperature dependence shows two regions with different
activation energies. The dielectric constant decreases with an increase
in the treatment temperature. The Z'' frequency dependence shows two
relaxation peaks, one at frequencies > 1 kHz and another at low
frequencies. The mean value of the relaxation times shifts to higher
frequencies with an increase in measurement temperature. These
dielectric behavior was an R-0(R1CPE1)(R2CPE2) equivalent circuit, using
a complex non-linear least squares algorithm. The electrical and
dielectrical behavior, of the glass materials, shows the important role
of the treatment temperature on the gel-glass structure. (c) 2006
Elsevier B.V. All rights reserved.
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