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.