title: Synthesis and structural/physical properties of U3Fe2Ge7: a single-crystal study.
abstract: 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 TC = 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 μB per formula unit at 2 K. The moment per Fe atom is 0.2 μB, as follows from Mössbauer 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.
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic , Na Slovance 2, 182 21 Prague, Czech Republic.|Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa , P-2695-066 Bobadela, Portugal.
authors.forename: Margarida S
authors.initials: MS
authors.lastname: Henriques
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic , Na Slovance 2, 182 21 Prague, Czech Republic.|Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf , D-01314 Dresden, Germany.
authors.forename: Denis I
authors.initials: DI
authors.lastname: Gorbunov
authors.affiliation: Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa , P-2695-066 Bobadela, Portugal.
authors.forename: João C
authors.initials: JC
authors.lastname: Waerenborgh
authors.affiliation: Institut des Sciences Chimiques de Rennes, Chimie du Solide et Matériaux, Université Rennes 1, UMR CNRS 6226 , 263 Avenue du Général Leclerc, 35042 Rennes, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Pasturel
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic , Na Slovance 2, 182 21 Prague, Czech Republic.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Andreev
authors.affiliation: Institute of Physics, Academy of Sciences of the Czech Republic , Na Slovance 2, 182 21 Prague, Czech Republic.
authors.forename: Michal
authors.initials: M
authors.lastname: Dušek
authors.affiliation: Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf , D-01314 Dresden, Germany.
authors.forename: Yurii
authors.initials: Y
authors.lastname: Skourski
authors.affiliation: Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University , Ke Karlovu 5, 121 16 Prague, Czech Republic.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Havela
authors.affiliation: Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa , P-2695-066 Bobadela, Portugal.
authors.forename: António P
authors.initials: AP
authors.lastname: Gonçalves