Improved electrical properties of cadmium substituted cobalt ferrites nano-particles for microwave application

• Preparation of homogeneous, spherical and single phase well crystallized cobalt ferrites.
• A simple and economical PEG assisted wet chemical co-precipitation method has been used.
• Increased in DC electrical resistivity and activation energy.
• Decease in dielectric constant used for microwave absorber.
• AC conductivity of Cd2+ substituted Co-ferrites increases.

Cadmium substituted cobalt ferrites with formula CdxCo1−xFe2O4 (x=0.0, 0.2, 0.35, 0.5), have been synthesized by wet chemical co-precipitation technique. Electrical, morphological and Structural properties of the samples have been studied using DC electrical resistivity and Impedance analyzer, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD), respectively. XRD, SEM and AFM have been used to study the structural parameters such as measured density, lattice constant, X-ray density, crystallite size and morphology of the synthesized nano-particles. Debye–Scherrer formula has been used for the estimation of crystallite sizes. The estimated crystallite sizes were to be 15–19±2 nm. Hopping length of octahedral and tetrahedral sites have been calculated using indexed XRD data. The porosity and lattice constant increased as Cd2+concentration increases. DC electrical resistivity was performed using two probe technique. The decrease of resistivity with temperature confirms the semiconducting nature of the samples. The dielectric properties variation has been studied at room temperature as a function of frequency. Variation of dielectric properties from 100 Hz to 5 MHz has been explained on the basis of Maxwell and Wagner’s model and hoping of electrons on octahedral sites. To separates the grains boundary and grains of the system CdxCo1−xFe2O4 the impedance analysis were performed.

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