IST/ITN, Instituto Superior Técnico, UTL, CFMC-UL, Sacavém, Portugal.
J Phys Condens Matter. 2013 Feb 13;25(6):066010. doi: 10.1088/0953-8984/25/6/066010. Epub 2013 Jan 11.
Magnetic properties of the intermetallic compound U(2)Fe(3)Ge were studied on a single crystal. The compound crystallizes in the hexagonal Mg(2)Cu(3)Si structure, an ordered variant of the MgZn(2) Laves structure (C14). U(2)Fe(3)Ge displays ferromagnetic order below the Curie temperature T(C) = 55 K and presents an exception to the Hill rule, as the nearest inter-uranium distances do not exceed 3.2 Å. Magnetic moments lie in the basal plane of the hexagonal lattice, with the spontaneous magnetic moment M(s) = 1.0 μ(B)/f.u. at T = 2 K. No anisotropy within the basal plane is detected. In contrast to typical U-based intermetallics, U(2)Fe(3)Ge exhibits very low magnetic anisotropy, whose field does not exceed 10 T. The dominance of U in the magnetism of U(2)Fe(3)Ge is suggested by the (57)Fe Mössbauer spectroscopy study, which indicates very low or even zero Fe moments. Electronic structure calculations are in agreement with the observed easy-plane anisotropy but fail to explain the lack of an Fe contribution to the magnetism of U(2)Fe(3)Ge.
研究了金属间化合物 U(2)Fe(3)Ge 的磁性。该化合物在单晶中结晶为六方 Mg(2)Cu(3)Si 结构，这是 MgZn(2)Laves 结构(C14)的有序变体。U(2)Fe(3)Ge 在居里温度 T(C) = 55 K 以下表现出铁磁性有序，并且违反了 Hill 规则，因为最近的铀-铀距离不超过 3.2 Å。磁矩位于六方晶格的基面，自发磁矩 M(s) = 1.0 μ(B)/f.u.在 T = 2 K。在基面内未检测到各向异性。与典型的基于 U 的金属间化合物不同，U(2)Fe(3)Ge 表现出非常低的磁各向异性，其场强不超过 10 T。(57)Fe Mössbauer 光谱研究表明 U 在 U(2)Fe(3)Ge 磁体中的主导地位，表明 Fe 磁矩非常低甚至为零。电子结构计算与观察到的易面各向异性一致，但无法解释 Fe 对 U(2)Fe(3)Ge 磁性没有贡献的原因。
