Sn-119 Mossbauer study of the compound UAuSn

A detailed Mossbauer investigation of the equiatomic stannide UAuSn was undertaken to shed light on its local magnetic properties, Careful analysis of Mossbauer spectra recorded in a wide temperature range 4.2 K to 300 K showed a huge distribution of transferred hyperfine fields at Sn-199 observed below T-N = 35 K. The observed coexistence of magnetic and nonmagnetic components close to the magnetic transition points to the presence of magnetic inhomogeneities in the system under study. The derived distribution function, F(H-eff), is discussed in terms of local disorder and 5f-(s,p,d) hybridization. Temperature dependencies of the first, second and third moments of the magnetic hyperfine field distribution provide new clues as to the origin of existing discrepancies found in the literature between the magnetic moments of uranium in UAuSn, obtained by the different experimental methods.