A Raman Study of Morphotropic Phase Boundary in PbZr1-xTixO3 at low   temperatures
  Raman spectra of PbZr1-xTixO3 ceramics with titanium concentration varying between 0.40 and 0.60 were measured at 7 K. By observing the concentration-frequency dependence of vibrational modes, we identified the boundaries among rhombohedral, monoclinic, and tetragonal ferroelectric phases. The analysis of the spectra was made in the view of theory group analysis making possible the assignment of some modes for the monoclinic phase. 
K. C. V. Lima, A. G. Souza, A. P. Ayala, J. Mendes Filho, P. T. C.   Freire, F. E. A. Melo, E. B. Ara\'ujo and J. A. Eiras