Effect of Gd3+ substitution on dielectric behaviour of copper-cadmium ferrites
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The dielectric constant, ε′, loss tangent (tan δ) and a.c. resistivity (ρa.c.) are measured in the frequency range of 100 Hz to 5 MHz for the series of samples Cdx Cu1−xFe2−yGdyO4 prepared by the ceramic technique. The dispersion in ε′ for all the values of x and y=0 and 0.1 shows a normal behaviour except for y=0.1 and x=0.4. The lowering of dielectric intensity in substituted ferrites (y=0.1) and fast dispersion of (ρa.c.) with frequency, are explained as due to the reduced number of Fe3+ participating in the polarization process and the hindrances caused by Gd3+ to the polarization process by localizing Fe2+ ions thereby increasing the resistivity and activation energy. The dispersion in tan δ for unsubstituted samples (y=0.0) shows a normal trend while substituted samples (y=0.1) show relaxation behaviour, which is explained by existing theories.
KeywordsPolymer Activation Energy Ferrite Dielectric Constant Material Processing
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