Magnetic properties of NP2T3X4 compounds

The magnetic and electronic properties of Np2T3X4 compounds, as inferred fr om Np-237 Mossbauer spectroscopy, magnetization and resistivity measurement s, are reported. NP2Mo3Si4 orders at T-N approximate to 47 K into an AF pha se and becomes ferrimagnetic at T' approximate to 38 K, Np2Tc3Si4 and Np2Tc 3Ge4 order antiferromagnetically, respectively, at T-N approximate to 19 K and T-N approximate to 15 K. All compounds exhibit complex Mossbauer spectr a which were reproduced assuming the occurrence of three distinct Np3+ site s with different magnetic moments and moreover an extra, zero-moment Np3+ s ite is always associated with the AF-phases. The variation of the magnetic properties along the series may be explained by Np-transition metal hybridi zation and Kondo effect. (C) 2001 Elsevier Science B.V. All rights reserved .