Electric and magnetic properties of lanthanum barium cobaltite |
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| Authors: | Iga Szpunar Sebastian Wachowski Tadeusz Miruszewski Kacper Dzierzgowski Karolina Górnicka Tomasz Klimczuk Magnus Helgerud Sørby María Balaguer José M. Serra Ragnar Strandbakke Maria Gazda Aleksandra Mielewczyk-Gryń |
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| Affiliation: | 1. Department of Solid State Physics, Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Gdansk, Poland;2. Department for Neutron Materials Characterization, Institute for Energy Technology, Kjeller, Norway;3. Instituto de Tecnología Química (Universidad Politécnica de Valencia – Consejo Superior de Investigaciones Científicas), Valencia, Spain;4. Department of Chemistry, Centre for Materials Science and Nanotechnology, University of Oslo, FERMiO, Oslo, Norway |
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| Abstract: | The cubic Ba0.5La0.5CoO3-δ 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 θP = 198(3) K and µeff = 2.11(2) µB. 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. |
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| Keywords: | electrical properties magnetic materials/properties perovskites |
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