Magnetic properties of Np2T3X4 compounds

Abstract The magnetic and electronic properties of Np 2 T 3 X 4 compounds, as inferred from 237 Np Mossbauer spectroscopy, magnetization and resistivity measurements, are reported. Np 2 Mo 3 Si 4 orders at T N ≈47 K into an AF phase and becomes ferrimagnetic at T ′′≈38 K, Np 2 Tc 3 Si 4 and Np 2 Tc 3 Ge 4 order antiferromagnetically, respectively, at T N ≈19 K and T N ≈15 K. All compounds exhibit complex Mossbauer spectra which were reproduced assuming the occurrence of three distinct Np 3+ sites with different magnetic moments and moreover an extra, zero-moment Np 3+ site is always associated with the AF-phases. The variation of the magnetic properties along the series may be explained by Np-transition metal hybridization and Kondo effect.