Magnetic, thermal, and transport properties of single-crystalline U3Fe4Ge4

• Published in: Journal of alloys and compounds 2013-04, Vol.555, p.304-310
• Main Authors: Henriques, M.S., Gorbunov, D.I., Waerenborgh, J.C., Havela, L., Andreev, A.V., Skourski, Y., Gonçalves, A.P.
• Format: Article
• Language: English
• Subjects: Actinide alloys; Alloys; Anisotropy; Electronics; Ferromagnetism; Heat capacity; High magnetic fields; Magnetic moment; Magnetization; Single crystal; Single crystals; Specific heat; Transport properties; Uranium intermetallics
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.12.092

► U3Fe4Ge4 represents pure uranium magnetism as iron has no ordered magnetic moment. ► Magnetic, thermal, and transport properties were studied on a U3Fe4Ge4 single crystal. ► U3Fe4Ge4 is a strongly itinerant 5f ferromagnet. ► A strong easy-axis anisotropy is observed that results in a gap excitation behavior. Magnetic, thermal, and transport properties of a U3Fe4Ge4 single crystal have been studied. The compound crystallizes in the orthorhombic Gd3Cu4Ge4 structure type. U3Fe4Ge4 displays ferromagnetic order below the Curie temperature TC=18K. The magnetism originates from the uranium sublattice, as iron atoms have no ordered magnetic moments. U3Fe4Ge4 exhibits a pronounced easy-axis anisotropy with the anisotropy field exceeding 60T. The spontaneous magnetic moment is Ms=1.2μB/f.u. at T=2K. Magnetic contribution to specific heat shows a gap excitation behavior with Δ=4meV, which can be related to the magnon gap due to the anisotropy. The Sommerfeld coefficient of the electronic specific heat is γ=57mJ/(mol-UK2) in the ordered state, whereas it is much higher (145mJ/(mol-UK2) if derived from the paramagnetic state. Electrical resistivity has very high values on the mΩcm range.