Structural, Electrical and Dielectric of Fe-Doped CaMn1-xFexO3-0.5x (x=0.0 and 0.20)

This work focuses on the structural and electrical properties of CaMn1-xFexO3-0.5x (x=0.0 and 0.20) perovskite compounds prepared using the ceramic method. XRD patterns confirm the formation of the orthorhombic structure with Pnma space group for the samples, and Rietveld method was used to estimate their different structural parameters. Refinement results show that the cell parameters and unit cell volume increase with increasing Fe content. The complex impedance spectroscopy technique was used to investigate the frequency and temperature dependence of electrical conductance and electrical impedance. The total conductance curves of the sample are found to obey Jonscher power law GT()=G(dc)+G(ac)=G(dc)+A(n) with an increase in frequency exponent (n) as temperature increases. Electrical impedance results show the presence of the electrical relaxation phenomenon for the samples. The activation energy deduced from the analysis of the conductance curves matches very well with the value estimated from the relaxation time, indicating that relaxation process and electrical conductivity are attributed to the same defect. The Nyquist representations have been analyzed using a proposed electrical circuit, and the results show that the grain boundary contribution is responsible to the conduction mechanism of the prepared samples.