Raman scattering study of Tb(V1-xPx)O4 single crystals

The polarized Raman spectra of a series of isostructural vanadate/phosphate compounds of the form: Tb(V1-xPx)O-4 with 0less than or equal toxless than or equal to0.75 have been investigated at room temperature. While the observed Raman spectra are generally consistent with group theory predictions for a body-centered tetragonal crystal structure (D-4h(19)), due to the replacement of P for V, additional spectral features induced by the disorder of the mixed vanadate/phosphate system are also observed. In particular, all of the external lattice modes are characterized by a one-phonon-like behavior, while the behavior of the internal modes of the (V,P)O-4 tetrahedron is two-phonon-like. (C) 2004 American Institute of Physics.