C. W. A. Paschoal

Spin-phonon coupling in Y2NiMnO6 double perovskite probed by Raman spectroscopy

Temperature-dependent Raman spectroscopy measurements in Y2NiMnO6 ceramics were performed in the 20u2009K–850u2009K range. A detailed analysis of the temperature dependence of the phonon energy of the oxygen octahedra stretching mode shows an anomalous softening below the Curie temperature. This effect was ascribed to a spin-phonon coupling, suggesting that the oxygen octahedra stretching vibrational mode stabilizes the magnetic interaction. The observed spin-phonon coupling is stronger than those reported in other Re2NiMnO6 double perovskites, suggesting that the rare earth ionic radius is not the unique parameter influencing the magnitude of this effect.

Raman and infrared spectroscopic studies of the Li3Na3In2F12 fluoride garnet

Single crystals of the Li3Na3In2F12 fluoride garnet have been studied by Fourier-transform infrared spectroscopy and Raman scattering. Polarized Raman spectra were recorded at low temperatures showing that the room-temperature phase is stable down to 7 K. Selected scattering geometries allow us to identify the Raman-active phonons based on the factor group analysis. The infrared reflectance spectrum was measured at room temperature and analysed on the basis of the four-parameter semi-quantum model.

Low-temperature phase transition in CsInF4

Abstract Temperature-dependent Raman spectra are recorded in order to investigate the stability of the room temperature orthorhombic D 2 h 13 structure of CsInF 4 . The appearance of new lines as well as a soft-like mode below 283xa0K is observed. These new features indicate that the D 2 h 13 ( Pmmn ) phase undergoes a structural modification for temperatures T