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

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.