Chlorine Insertion Promoting Iron Reduction in Ba–Fe Hexagonal Perovskites: Effect on the Structural and Magnetic Properties

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• 作者：Laura Serrador ; María Hernando ; José L. Martínez ; José M. González-Calbet ; Aurea Varela ; F. Javier García-García ; Marina Parras
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 20, 2016
• 年：2016
• 卷：55
• 期：12
• 页码：6261-6270
• 全文大小：609K
• 年卷期：0
• ISSN：1520-510X

文摘

BaFeClb>0.13(2)b>Ob>2.48(2)b> has been synthesized and studied. A proper tuning of the synthetic route has been designed to stabilize this compound as a single phase. The thermal stability and evolution, along with the magnetic and structural properties are reported here. The crystal structure has been refined from neutron powder diffraction data, and it is of the type (hhchc)b>2b>-10H. It is stable up to a temperature of 900 °C, where the composition reads BaFeClb>0.13(2)b>Ob>2.34(2)b>. The study by electron microscopy shows that the crystal structure suffers no changes in the whole BaFeClb>0.13(1)b>Ob>3–yb> (2.34 ≤ 3 – y ≤ 2.48) compositional range. Refinement of the magnetic structure shows that the Fe is antiferromagneticaly ordered, with the magnetic moment parallel to the ab plane of the hexagonal structure. At higher temperature, a nonreversible phase transition into a (hchc)-4H structure type takes place with overall composition BaFeClb>0.13(1)b>Ob>2.26(1)b>. Microstructural characterization shows that, in some crystals, this phase intergrows with a seemingly cubic related phase. Differences between these two crystalline phases reside in the chlorine content, which keeps constant through the phase transition for the former and disappears for the latter.