DC and AC electrical properties of Sr_2-xLi_xFeMnO ₆ compound

The variations of dc conductivities (σ) of the Sr _2-xLi_xFeMnO₆ double perovskite system over a range of temperatures (100 - 300 K) and for several concentrations (0≤ × ≤ 0.4) of incorporated Li⁺ ions are well described by the equation σ = (B/T) exp(-E_a/kT) and show a decrease with decreasing temperature for a given doping. At a given temperature, a tends to decrease with increasing x. The derived activation energy shows a gradual increase with x with a range of values that are lower than what is usually reported. The measured ac impedance is used to extract the relaxation frequencies as a function of composition and temperature.