Анотація:
The refraction n and absorption χ indices of paramagnetic Сo-Cr alloys with
10, 20 and 35% chromium concentrations were measured within the spectral range 0.23
to 2.8 µm (0.44…5.36 eV) at room temperature by spectral ellipsometric methods. Based
on these data, the dielectric permittivity ε, optical conductivity σ and reflection
coefficient R at normal incidence were calculated. The dispersion of optical conductivity
σ(hν) and dispersion curves of residual optical conductivity σ(hν) = σ(hν) – (1 – c) σCo(hν) were analyzed in detail (c – Cr impurity concentration, σCo(hν) – optical
conductivity of Co solvent). It has been ascertained that new impurity bands are formed
in the electronic spectrum of Co solvent when Cr impurities are added, which are
responsible for the extra absorption in Сo-Cr alloys. The localization of impurity energy
levels in Co-Cr alloys at 1.8…2.0 eV above the Fermi level has been suggested.