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Abstract: We studied the optical properties of the intermetallic compounds ScFe2and ErFe2in a wide spectral range of 0.22–15 μm. The frequency dependences of the optical constants were determined, and several electronic and spectral characteristics were calculated using spectrometric ellipsometry. The nature of quantum absorption of light in these materials is discussed based on a comparative analysis of experimental and theoretical spectra of interband optical conductivity. The dispersion dependences of these spectra can be qualitatively interpreted using the previously calculated densities of electronic states.

Abstract: Influence of the chemical pressure (x) in single crystals of FexMn1 –xS (0.12 = x= 0.29) on the spin state of iron ions was studied by Mössbauer spectroscopy in the temperature range from 4.2 to 300 K. Peculiarities of formation of the paramagnetic and antiferromagnetic phases of solid solutions were found. Substitution of Fe2+cations in the high-spin state for Mn2+was found to occur in FexMn1 –xS as xchanges. A decrease in the distance between the ions in FexMn1 –xS induces changes in the state of the Fe2+ions in the samples with x= 0.25 and 0.29. The asymmetry parameter of the electric field gradient (EFG) tensor and the angle between the directions of the magnetic moment and the principal axis of the electric field gradient were found to change in the magnetically ordered phase at 4.2 K; the angle between the magnetic moment and the electric field gradient axis changes from 21° in the sample with x= 0.12 to 33° when x= 0.29.

Abstract: The ellipsometric studies of the optical properties of intermetallic YFe2and TbFe2compounds have been performed in the wavelength range 0.22–15 μm, and a number of electronic and spectral characteristics have been determined. The nature of the interband light absorption in these materials is discussed based on a comparative analysis of the experimental and theoretical spectra of the optical conductivity. The experimental optical conductivities of the compounds in the region of quantum electron transitions are shown to agree qualitatively with the spectra calculated from the densities of electronic states.

Abstract: The electronic structure and the optical properties of the DyFe2Si2compound have been studied. The calculations of the energy band spectrum taking into account the spin polarization have been performed in an approximation of the local electron density with a correction for strong correlation effects in the 4fshell of a rare-earth metal (the GGA + Umethod). The optical properties have been studied by the ellipsometric method in a wide range of wavelengths; a number of spectral and electronic characteristics have been determined. It is shown that the optical conductivity of this compound in the region of the interband light absorption is adequately explained in the framework of the performed calculation of electronic states.