Analysis of the low-frequency spectrum of the cubic noncentrosymmetric ferrimagnet Cu2OSeO3

The IR reflectance spectra of the cubic noncentrosymmetric ferrimagnet Cu2OSeO3 (T-C approximate to 60 K) were investigated in the temperature range 10-80 K. Detailed analysis of the symmetry and composition of vibrational modes was conducted on the basis of Raman scattering data and data obtained in this investigation. 68 out of 69 modes consistent with the crystal lattice symmetry were revealed. Some spectral features found in the magnetically ordered phase were studied. The bands at 280 and 421 cm(-1) related to the spectrum of two-magnon light scattering were observed. Dynamic magnetoelectric coupling was found to be responsible for the intensity redistribution in the Raman and IR spectra for the threefold degenerate modes of F-symmetry (modes at 84, 205, and 269 cm(-1)). No change associated with magnetic ordering was observed in the symmetry of the crystal structure. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4723668]