Mossbauer and magnetization studies of the cubic NpPd 3− xRh x intermetallic compounds

Abstract

Susceptibility and Mossbauer absorption studies of 237Np in the cubic NpPd 3− x Rh x (0 ⩽ x ⩽ 3) intermetallic compounds were performed. The results show a decrease of the ordering temperature as a function of x (for x = 0.0, 0.1, 0.25, T N = 50, 27, 15 K respectively), a decrease of the paramagnetic effective moment and a large increase of the magnetic hyperfine field acting on the Np nucleus ( μ eff = 2.7 μ B , H eff = 3.3 mOe for NpPd 3, and μ eff = 1.9 μ B , H eff = 4.8 mOe for NpPd 2.75Rh 0.25). This unusual magnetic behavior indicates that in the NpM 3 systems there is no simple relation between the hyperfine field and the magnetic moment. The magnetic properties are mainly determined by the M component and the corresponding band structure.