Thermodynamic and Electronic Properties of DyNi$_{4}$Si Compound

Electronic and thermodynamic properties of the ternary DyNi₄Si compound, crystallizing in the hexagonal CaCu₅ structure (P6/mmm space group) were studied by X-ray photoelectron spectroscopy (XPS) and heat capacity measurements. DyNi₄Si is ferromagnetic with magnetic moment 7.9 mu_B/f.u. at 4.2 K (in H = 9 T) and Curie temperature T_C = 11 K. The heat capacity measurements have shown that DyNi₄Si is characterized by electronic heat capacity coefficient gamma = 72 mJ/mol K. Zero field heat capacity reveals a peak close to the magnetic ordering temperature, which gets suppressed in an applied field of 5 T. The valence band of the XPS spectra is determined mainly by the Ni(3d) and Dy(4f) contributions. The slight shift of peaks´ positions towards the higher binding energy by about 0.3 eV in respect to the pure Dy is probably due to the different crystalline electric field for Dy in the DyNi₄Si compound.