Raman scattering in a LiNiPO4 single crystal

The complete Raman spectra of a single crystal of LiNiPO4 for a wide temperature range are reported. Of the 36 Raman-active modes predicted by group theory, 33 have been detected. The spectra are successfully analyzed in terms of internal modes of the (PO4)(3-) group and external modes. Multiphonon Raman scattering is also discussed. Low-frequency lines, observed in the antiferromagnetic phase, are assigned to magnon scattering and are discussed briefly. (C) 2002 American Institute of Physics.