Peculiar Properties of Electrochemically Oxidized SmBaCo2−xMnxO5+δ (x = 0; 0.5 and 1) A-Site Ordered Perovskites.

Fully-stoichiometric SmBaCo_2-xMn_xO₆ oxides (x = 0, 0.5, 1) were obtained through the electrochemical oxidation method performed in 1 M KOH solution from starting materials having close to equilibrium oxygen content. Cycling voltammetry scans allow us to recognize the voltage range (0.3–0.55 V vs. Hg/HgO electrode) for which electrochemical oxidation occurs with high efficiency. In a similarly performed galvanostatic experiment, the value of the stabilized voltage recorded during the oxidation increased with higher Mn content, which seems to relate to the electronic structure of the compounds. Results of the iodometric titration and thermogravimetric analysis prove that the proposed technique allows for an increase in the oxygen content in SmBaCo_2-xMn_xO_5+δ materials to values close to 6 (δ ≈ 1). While the expected significant enhancement of the total conductivity was observed for the oxidized samples, surprisingly, their crystal structure only underwent slight modification. This can be interpreted as due to the unique nature of the oxygen intercalation process at room temperature. [ABSTRACT FROM AUTHOR]