Discovery and Characterization of Antiferromagnetic UFe₅As₃

Abstract

This work presents a study on a new uranium iron arsenide UFe 5 As 3 . By implementing Bi-flux synthesis, we were able to grow mm-sized single crystals of this compound, which show twinning. UFe 5 As 3 is one of only two known uranium iron arsenides. It adopts a monoclinic, UCr 5 P 3 -type crystal structure (space group P2 1 /m, Pearson symbol mP18, a = 7.050(2) Å, b = 3.8582(9) Å, c = 9.634(1) Å, β = 100.25(1)°). The magnetic susceptibility of UFe 5 As 3 indicates it to be an antiferromagnet with T N = 47 K and μ eff = 4.94 μ B per formula unit, signaling that both U and Fe are likely magnetic in this material. The material appears to be anisotropic, with a small (likely ferromagnetic) spin reorientation transition around T = 29 K. The Sommerfeld coefficient γ 0 = 135 mJ mol −1 K −2 suggests enhanced effective electron mass in UFe 5 As 3 , while electrical resistivity indicates metallic, Kondo-like behavior.

Synthesis, magnetic and NMR spectroscopic properties of the MAl5Pt3 series (M = Ca, Y, La–Nd, Sm–Er)

“…In contrast to UFe 5 As 3 and related compounds no twinning was observed. 69 Details of the structure determination, atomic parameters and interatomic distances can be found in Tables 2–4. When looking at the refined anisotropic displacement parameters (ADP) of the atoms, Er exhibits a value of 85 pm 2 , which is larger than the one of Pt and Al.…”