LOW-TEMPERATURE PHASE TRANSITIONS AND MAGNETIC SUSCEPTIBILITIES OF LOW-DIMENSIONAL URANIUM FLUORIDES

Article abstract of DOI:10.1007/BF00755199

Measurements have been made on the magnetic susceptibilities of the quasi-one-dimensional magnetic α-UF5 and the cluster magnetic U2F9 (a four-nuclear type) over the range 4.2-300 K.The Curie-Weiss law applies for α-UF5 above 200 K, with μ_ef = 2.37_μB, θ = -148 K; that law also applies to U2F9 above 150 K, with μ_ef = 2.9_μB and θ = 118 K.The antiferromagnetic ordering is discussed for the one-dimensional chains in α-UF5 together with the phase transition observed in U2F9 at 6 K.It is assumed that the U⁴⁺ and U⁵⁺ valency states are stabilized below the phase-transition point, and only then can U2F9 be cosidered as the compound UF4.UF5.