A.C Conductivity, dielectric spin relaxation and impedance spectroscopy studies of cobalt substituted calcium nano ferrite for high frequency applications

Abstract

In the present research article cobalt substituted calcium nano ferrites CoxCa1-xFe2O4 (x = 0, x = 0.05, x = 0.1, x =0.15, x = 0.2, x =0.25) CoCAF were prepared by the novel solution combustion method. The PXRD, TEM, SEM and LCR meter were employed to evaluate the structural and electrical properties of the samples. The PXRD analysis confirms the formation of spinel ferrites with single phase up to x = 0.1, where as for x <0.1 an extra intermediate phase has been detected. The average crystallite size is of the order 27 nm-55 nm and it is in good agreement with the TEM measurements. The morphology studies were performed by SEM. The Real and imaginary part of the permittivity, dielectric loss, ac conductivity, electric modulus are calculated for the Cobalt doped Calcium nanoferrites. The decrease in permittivity and dielectric loss with increase in applied frequency is in accordance with Maxwell Wagner theory. The analysis of complex modulus spectrum confirms the non Debye nature of conductivity relaxation for the CoCAF samples and indicates the large grain boundary resistance. The high value of permittivity of the CoCaF makes the material suitable for energy storage applications, for microwave devices and high frequency applications. Copyright © 2018 American Scientific Publishers. All right reserved.