Electric modulus, scaling and ac conductivity of La2CuMnO6 double perovskite

Abstract

A sample of La2CuMnO6 (LCM) was synthesized through the standard solid state reaction method. X-ray diffraction experiments and Rietveld analysis reveal that the material crystallizes in an orthorhombic structure. SEM image displayed well-defined regular shaped nearly spherical and unequal grains with grain-size lies between 2.5 and 3.0 μm ranges. Frequency dependence of dielectric, electric modulus and ac conductivity of LCM has been studied as a function of both frequency and temperatures. The conduction mechanism is explained using universal power law (σ (ω, T) = B ωn(T)). The Kohlrausch–Williams–Watts (KWW) model approaches were employed to fit frequency response curves of M′ and M″. The large asymmetry of M″(f) peaks were explained by stretched exponent parameter (β). Activation energy values suggest that the conduction mechanism and relaxation process have a different origin. The ε′ and ε″, as a function of normalized frequency, exhibit better master curves than M″ vs M′ data.