Impedance spectroscopy study of electrical response and correlation with structural properties in the La2SrFe2CoO9 triple complex perovskite

The triple perovskite with formula La2SrFe2CoO9 has been synthesized and experimentally studied. The samples were obtained by the solid-state reaction method. Scanning Electron Microscopy images show a strongly diffused granular surface morphology with mean grain size of 1 μm and Electron Dispersive X-ray spectra evidence that the chemical composition of sample is in good agreement with the nominal values of the stoichiometric formula. The electrical transfer functions were studied through the Impedance Spectroscopy technique in the range from 1 mHz to 100 KHz and in the temperature, range from 75 to 295 K. The interpretation of BODE and NYQUIST - diagrams allows the development of an equivalent circuit which explain the behavior of the electrical response throughout the frequency range. The conductance measurements showed the dependence of the conduction mechanisms with frequency and temperature. Structural and impedance properties are correlated allowing to propose mechanisms of charge transfer.