Structural and impedance spectroscopy properties of La0.8Ba0.1Ca0.1Mn1−xRuxO3 perovskites

Abstract Polycrystalline samples La 0.8 Ba 0.1 Ca 0.1 Mn 1−x Ru x O 3 (x=0 and 0.075) were prepared by sol-gel-based Pechini method. The X ray diffraction study has shown that all the samples exhibit a single phase with rhombohedral structure (space group R 3 c , no. 167). The complex impedance has been investigated in the temperature range 160–320 K and in the frequency range 40 Hz–1 MHz. The imaginary part of the complex impedance (Z′′) frequency dependence revealed one relaxation peak. The Cole-Cole plots of the impedance values exhibited a semi –circular arc that can be described by an R 1 +(R 2 //Z CPE ) electrical equivalent circuit. The conductance spectra have been investigated by the Jonscher universal power law: G(ω)=G DC +Aω n , where ω is the frequency of the ac field, and n is the exponent. The activation energy obtained both from the conductance and from time relaxation analyses are very similar, and hence the relaxation process may be attributed to the same type of charge carriers.