Half-Metallicity in Pb2CoReO6 Double Perovskite and High Magnetic Ordering Temperature in Pb2CrReO6 Perovskite

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• 作者：Maria Retuerto ; Man-Rong Li ; Peter W. Stephens ; Javier S谩nchez-Ben铆tez ; Xiaoyu Deng ; Gabriel Kotliar ; Mark C. Croft ; Alexander Ignatov ; David Walker ; Martha Greenblatt
• 刊名：Chemistry of Materials
• 出版年：2015
• 出版时间：June 23, 2015
• 年：2015
• 卷：27
• 期：12
• 页码：4450-4458
• 全文大小：461K
• ISSN：1520-5002

文摘

Pb₂MReO₆ (M = Co, Cr) perovskites were prepared by high pressure鈥揾igh temperature method. Rietveld refinements of synchrotron powder X-ray diffraction show that the crystal structure of Pb₂CoReO₆ is trigonal (space group R-3) with almost complete ordering of Co and Re cations, while Pb₂CrReO₆ (space group Pm-3m) is a cubic perovskite with one single site for Cr and Re atoms. The difference between the symmetry and the degree of order was further clarified by X-ray absorption spectroscopy that establishes formal oxidation states in these phases as Pb₂Co²⁺Re⁶⁺O₆ and Pb₂Cr³⁺Re⁵⁺O₆. Pb₂CrReO₆ is a simple perovskite with a high magnetic ordering temperature of 643 K. Pb₂CoReO₆ is a double perovskite with 鈭?3% high field negative magnetoresistance at 10 K and 9 T. First-principles calculations of Pb₂CoReO₆ indicate a half metallic electronic structure.