Raman spectroscopic study of Mn-doped Bi4Ge3O12

Raman spectra of pure and Mn-doped Bi4Ge3O12 crystals are measured and the observed peaks are assigned through calculating the vibrational modes of di fferent clusters representative for the Bi4Ge3O12 structure. The doping wit h Mn affects only the polar modes and the resulting changes in the spectra can be explained by anisotropic embedding of Mn into the host lattice of Bi 4Ge3O12 which leads to an increase in the anisotropy of the long-range inte ratomic interactions. (C) 1999 Elsevier Science Ltd. All rights reserved.