Evolution of the optical properties of DyNi5 − x Al x compounds in dependence of aluminum concentration

Abstract

The refractive (n) and absorption (k) indices of intermetallic DyNi5 − xAlx compounds (x = 0, 0.5, 1, 1.5, 2) have been measured by ellipsometry at room temperature in the spectral range of 0.22–15 μm. It is established that the replacement of nickel by aluminum atoms leads to significant changes in the dispersion relations of the optical conductivity σ(E) in the interband absorption range. With an increase in Al content, the spectrum σ(E) (containing three maxima for DyNi5) is gradually transformed into a single-peak structure. The results obtained are discussed on the basis of the data on the electronic spectrum of these compounds. Concentration dependences of the plasma and relaxation frequencies of conduction electrons are determined.