Magnetic properties of U (Fe x Al1?x )2 and U(Fe y Ni1?y )2 compounds

Abstract

The results of magnetic measurements and ferromagnetic resonance studies performed on U(Fe x Al1−x )2 and U(Fe y Ni1−y )2 compounds over a large temperature range are reported. The saturation magnetization decreases nearly linearly when substituting Fe by Al or Ni. In the composition range x<0.84 and y<0.81, the compounds are Pauli paramagnets, except in the region with y≲0.10. For UNi2 two types of magnetic behaviours are shown. This compound can be both a ferromagnet withT c =23.5 K and a Pauli paramagnet, depending on the crystal structure. Above the Curie temperatures, the reciprocal susceptibility for the compounds with x>0.84 and y>0.81 obeys a temperature dependence of the formX=X o+C(T-θ) −1. The effective iron moments decrease when substituting iron by nickel or aluminium. The ferromagnetic resonance measurements show that theg values are not composition-dependent. A linear variation of the mean iron magnetization with the exchange field is observed. Finally, the magnetic behaviour of iron in these compounds is analysed.