High field magnetisation and hall effect of U 3Sb 4 single crystals

Abstract

We have examined the Hall effect of U 3Sb 4 (T c = 146 K) in the paramagnetic and ferromagnetic ranges as well as the magnetisation along three principal directions at 4.2 K and in fields up to 35 T. Both ordinary and extraordinary Hall constants are positive, giving the hole concentration of 1.2 × 10 20 cm −3. The easy magnetic axis was found to be 〈100〉, and the uranium moment was determined to be 2μ B. Magnetisation jumps at 4.9 and 17.6 T in fields along the 〈111〈 and 〈110〉 direction, respectively, were also found. A microscopic spin model including crystal-field and anisotropic-exchange interactions predicts magnetisation behaviour in qualitative agreement with that observed experimentally for U 3X 4 (X = P, As, Sb) compounds, and it shows that the observed jumps are spin-orientational transitions.