Synthesis and Structural/Physical Properties of U3Fe2Ge7: A Single-Crystal Study

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• 作者：Margarida S. Henriques ; Denis I. Gorbunov ; Jo茫o C. Waerenborgh ; Mathieu Pasturel ; Alexander V. Andreev ; Michal Du拧ek ; Yurii Skourski ; Ladislav Havela ; Ant贸nio P. Gon莽alves
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：October 5, 2015
• 年：2015
• 卷：54
• 期：19
• 页码：9646-9655
• 全文大小：619K
• ISSN：1520-510X

文摘

A single crystal of U₃Fe₂Ge₇ was synthesized by the tin-flux method, and its structural and electronic properties were studied. The compound crystallizes in the orthorhombic crystal structure of La₃Co₂Sn₇ type with two Wyckoff sites for the U atoms. U₃Fe₂Ge₇ displays a ferromagnetic order below T_C = 62 K. Magnetization measurements in static (up to 14 T) and pulsed (up to 60 T) magnetic fields revealed a strong two-ion uniaxial magnetic anisotropy. The easy magnetization direction is along the c axis and the spontaneous magnetic moment is 3.3 渭_B per formula unit at 2 K. The moment per Fe atom is 0.2 渭_B, as follows from M枚ssbauer spectroscopy. The magnetic moments are oriented perpendicular to the shortest inter-uranium distances that occur within the zigzag chains in the ab plane, contrary to other U-based isostructural compounds. The magnetization along the a axis reveals a first-order magnetization process that allows for a quantitative description of the magnetic anisotropy in spite of its enormous energetic strength. The strong anisotropy is reflected in the specific heat and electrical resistivity that are affected by a gap in magnon spectrum.