Effect of Air Annealing on the Structural and Magnetic Properties of LaMnO3 Perovskite Produced by Reactive Spark Plasma Sintering Route

Autor: Y. Regaieg, Mohamed Koubaa, A. Cheikhrouhou, Judith Monnier, G. Delaizir, Benjamin Villeroy, C. Godart, L. Sicard, Frédéric Herbst, S. Ammar-Merah
Rok vydání: 2013
Předmět:
Zdroj: Journal of Superconductivity and Novel Magnetism. 26:1467-1471
ISSN: 1557-1947
1557-1939
DOI: 10.1007/s10948-012-1955-9
Popis: Perovskite-type lanthanum manganite (LaMnO3) was synthesized from Mn2O3 and La2O3 precursor powders using the Spark Plasma Sintering technique (SPS). The in situ reaction proceeds in a few minutes at 1000 °C under 50 MPa with a very high heating rate of 100 °C/min. The Rietveld refinement of the X-ray powder diffraction shows that LaMnO3 sample crystallizes in a perovskite structure of O′-type orthorhombic symmetry with Pbnm space group. After annealing at 1000 °C in air for 10 hrs, the symmetry changes to rhombohedral with R-3c space group. For the as prepared sample, two critical temperature points in the temperature dependence of the ZFC and FC magnetization occurring at 125 K and 145 K are observed. They are suggested to be related to A-type antiferromagnetic Neel temperature and ferromagnetic short range order, respectively. The ferromagnetic component in the annealed sample increases indicating the expected variation in the concentration of Mn3+ and Mn4+ ions, which was attributed to the oxygen stoichiometry effects.
Databáze: OpenAIRE
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