ChemInform Abstract: Stabilization and Study of SrFe1-xMnxO2 Oxides with Infinite-Layer Structure.

✍ Scribed by Maria Retuerto; Felix Jimenez-Villacorta; Maria J. Martinez-Lope; Maria T. Fernandez-Diaz; Jose A. Alonso

• Publisher: John Wiley and Sons
• Year: 2011
• Weight: 24 KB
• Volume: 43
• Category: Article
• ISSN: 0931-7597
• DOI: 10.1002/chin.201203016

✦ Synopsis

Stabilization and Study of SrFe 1-x Mn x O 2 Oxides with Infinite-Layer Structure.

-Layered oxides SrFe1-xMnxO2 (x = 0, 0.1, 0.2, 0.3) are prepared by reduction of three-dimensional perovskites SrFe1-xMnxO3-δ with CaH2 at 583 K for 2 d. The SrFe1-xMnxO3-δ precursor is obtained from stoichiometric amounts of Sr(NO3)2, FeC2O4, and MnCO3 in citric acid solution by decomposition at 600 °C (12 h) and subsequent annealing at 1000 °C (12 h). The products are characterized by powder XRD, powder neutron diffraction and XAS, XANES, and magnetic measurements. Mn 2+ ions are stabilized in an infinite-layer structure for x = 0.1 and 0.2. Attempts to prepare Mn-rich compositions beyond x = 0.2 are unsuccessful. The samples with x = 0, 0.1, and 0.2 crystallize in the tetragonal space group P4/mmm. For x = 0.1 and 0.2, both Fe and Mn are in divalent oxidation states. They are both four-fold coordinated to O atoms in (Fe,Mn)O4 square-planar units that share corners, giving rise to infinite layers separated by Sr 2+ ions. The magnetic coupling within these layers is extraordinarily strong, as demonstrated by a Neel temperature well above room temperature (453-523 K). Reoxidation of the materials at about 170 °C leads to new cubic perovskite phases, that is distinct from the original precursor phases. -(RETUERTO*, M.;