Electric and magnetic properties of Lanthanum Barium Cobaltite

"This is the peer reviewed version of the following article: Szpunar, Iga, Sebastian Lech Wachowski, Tadeusz Miruszewski, Kacper Dzierzgowski, Karolina Górnicka, Tomasz Klimczuk, Magnus H. Sorby, Maria Balaguer, José M Serra, Ragnar Strandbakke, Aleksandra Dorota Mielewczyk-Gry¿, and Maria Gazda. ¿Electric and Magnetic Properties of Lanthanum Barium Cobaltite¿. JOURNAL OF THE AMERICAN CERAMIC SOCIETY 103 (2020): 1809-18. https://doi.org/10.1111/jace.16865, which has been published in final form at https://doi.org/10.1111/jace.16865. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."
[EN] The cubic Ba0.5La0.5CoO3-delta was synthesized using solid state reaction. The structural properties were determined by the simultaneous refinement of Synchrotron Powder X-ray Diffraction and Neutron Powder Diffraction data. Iodometric titration was used to examine the oxygen stoichiometry and average cobalt oxidation state. Low-temperature magnetic studies show soft ferromagnetic character of fully oxidized material, with theta(P) = 198(3) K and mu(eff) = 2.11(2) mu(B). Electric measurements show the thermally activated nature of conductivity at low temperatures, whereas, due to the variable oxidation and spin state of cobalt, a single charge transport mechanism cannot be distinguished. Around room temperature, a wide transition from thermally activated conductivity to semi-metallic behavior is observed. Under the inert atmosphere, the oxygen content lowers and the cation ordering takes place, leading to coexistence of two, ordered and disordered, phases. As a result of this change, thermally activated conductivity is observed also at high temperatures in inert atmosphere.