Electrical, magnetic properties and electronic structure of non-stoichiometric DyNi2Mnx compounds

Abstract

The electrical, magnetic properties and electronic structure were studied in DyNi2Mnx (0 ≤ x ≤ 1.25) alloys. It was found that the alloys crystallize in a cubic MgCu2 Laves phase structure, in spite of the R (R = rare-earth element) to 3d-metal ratio changing from 1:2 to 1:3.25. The binary DyNi2 compound is characterized by a low temperature of magnetic ordering, TC = 22 K, since the 3d-band is almost filled by the valence electrons of Dy. The ordering temperature increases very sharply with the addition of Mn, reaches the maximum value of 120 K at x = 0.5 and then slightly decreases. A monotonous decrease of the magnetization is observed with increasing Mn content. The resistivity also varies with increasing x reflecting the changes in the conduction band. The XPS results show an increase of Mn3d states close to the Fermi level. The N(Ef) dependence for DyNi2Mnx strongly depends on f - d interactions and can be connected with the change of TC (x). The good relation between the magnetic, electrical properties and electronic structure has been found.