Optical absorption and structure of energy bands of GdNi5-xCu x intermetallic compounds

Optical properties of intermetallic compounds GdNi5 - x Cu (x) (x = 0, 0.5, 1, 1.5, and 2) have been studied in a spectral range from 0.22 to 15 mu m using the ellipsometry method. The substitution of copper for nickel has been found to lead to local changes in the interband optical conductivity spectra. A new quantum-absorption band, whose intensity increases substantially with increasing copper content, has been found at 3-4 eV. The relaxation and plasma frequencies of conduction electrons, which were calculated using data on the optical parameters, also depend on the concentration. Self-consistent calculations of the electronic structure of the intermetallic binary GdNi5 compound have been performed using the LSDA + U method. The density of electronic states for two spin projections and the frequency dependence of the interband optical conductivity of the compound have been calculated.