  Recently a new monoclinic phase in the PbZr(1-x)TixO3 ceramic system has been
reported by Noheda et al. for the composition x= 0.48. In the present work,
samples with Ti contents of x= 0.47 and 0.50, which are both tetragonal below
their Curie points, have been investigated. In the sample with x= 0.50, the
tetragonal phase was found to transform to a monoclinic phase at about 200 K as
the temperature was lowered. The sample with x= 0.47 showed a complicated
region of phase coexistence between 440-320 K, becoming rhombohedral at around
300 K. No further symmetry change was found down to 20 K. Dielectric
measurements for these two samples are also reported. On the basis of these
results, a preliminary phase diagram is presented. Optimum compositional
homogeneity is needed to properly characterize the new monoclinic region.
