Single crystal study of layered UnRhIn3n+2 materials: Case of the novel U2RhIn8 compound

We report on the single crystal properties of the novel U2RhIn8 compound studied in the context of parent URhIn5 and UIn3 systems. The compounds were prepared by In self-flux method. U2RhIn8 adopts the Ho2CoGa8-type structure with lattice parameters a = 4.6056(6) angstrom and c = 11.9911(15) angstrom. The behavior of U2RhIn8 strongly resembles that of the related URhIn5 and UIn3 with respect to magnetization, specific heat and resistivity except for magnetocrystalline anisotropy developing with lowering dimensionality in the series UIn3 vs. U2RhIn3 and URIn5. U2RhIn5 orders antiferromagnetically below T-N = 117K and exhibits a slightly enhanced Sommerfeld coefficient gamma=47 mJ mol(-1) K-2. Magnetic held leaves the value of Neel temperature for both URhIn5 and U2RhIn5 unaffected up to 9 T. On the other hand, TN is increasing when applying hydrostatic pressure up to 3.2 GPa. The character of uranium 5f electron states of U2RhIn5 was studied by first principles calculations based on the density functional theory. The overall phase diagram of U2RhIn8 is discussed in the context of magnetism in the related URhX5 and UX3 (X = In, Ga) compounds. (C) 2015 Elsevier B.V. All rights reserved.