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We report a Raman scattering study of single-crystalline homometallic oxyborate Mn2OBO3, a compound realizing a one-dimensional ribbon-structure. Phonon excitations as a function of temperature and light polarization are compared to lattice dynamical calculations, giving evidence for a strong coupling between lattice and magnetic degrees of freedom. Furthermore, a broader feature with a distinct structure emerges at low temperatures. Based on our theoretical analysis, we assign this signal to specific two-magnon scattering processes related to high energy flat-band magnon branches. [ABSTRACT FROM AUTHOR]

The electronic structure and optical properties of GdNi2Mnx compounds (x = 0, 0.4, 0.6) were investigated. Spin-polarized electronic structure calculations were performed in the approximation of local electron spin density corrected for strong electron correlations using the LSDA+U method. The changes in the magnetic moments and exchange interactions in GdNi2Mnx (x = 0, 0.4, 0.6) governing the increase in the Curie temperature with manganese concentration were determined. The optical constants of the compounds were measured by the ellipsometric method in the wide spectral range of 0.22–15 μm. The peculiarities of the evolution of the frequency dependences of optical conductivity with a change in the manganese content were revealed. Based on the calculated densities of electron states, the behavior of these dispersion curves in the region of interband absorption of light was discussed. The concentration dependences of several electronic characteristics were determined. [ABSTRACT FROM AUTHOR]

The electronic structure and optical properties of the SmNi5-xCux (x = 0, 1, 2) compounds are studied. The band spectra of the studied intermetallics were calculated with LDA + U + SO method supplementing the local density approximation with a correction for strong electron interaction on the shell of the rare-earth element. Optical properties were studied by ellipsometry method in the wide wavelength range. It was found that the substitution of copper for nickel leads to local changes in the optical conductivity spectra. Both the spectroscopic measurements and theoretical calculations demonstrate the presence of a broad absorption band around 4 eV associated with the Cu 3d Ni 3d electron transitions and increasing with the grown of copper content. The experimental dispersion curves of optical conductivity in the interband absorption region were interpreted using the results of the calculations. [ABSTRACT FROM AUTHOR]

The electronic structure and optical properties of the SmNi5-xCux (x = 0, 1, 2) compounds are studied. The band spectra of the studied intermetallics were calculated with LDA + U + SO method supplementing the local density approximation with a correction for strong electron interaction on the shell of the rare-earth element. Optical properties were studied by ellipsometry method in the wide wavelength range. It was found that the substitution of copper for nickel leads to local changes in the optical conductivity spectra. Both the spectroscopic measurements and theoretical calculations demonstrate the presence of a broad absorption band around 4 eV associated with the Cu 3d Ni 3d electron transitions and increasing with the grown of copper content. The experimental dispersion curves of optical conductivity in the interband absorption region were interpreted using the results of the calculations. [ABSTRACT FROM AUTHOR]

We report a Raman scattering study of single-crystalline homometallic oxyborate Mn2OBO3, a compound realizing a one-dimensional ribbon-structure. Phonon excitations as a function of temperature and light polarization are compared to lattice dynamical calculations, giving evidence for a strong coupling between lattice and magnetic degrees of freedom. Furthermore, a broader feature with a distinct structure emerges at low temperatures. Based on our theoretical analysis, we assign this signal to specific two-magnon scattering processes related to high energy flat-band magnon branches. [ABSTRACT FROM AUTHOR]