Low-temperature Raman studies of Pb(ZrxTi1-x)O-3 and Pb1-3y/2NdyTiO3 ceramics

Raman scattering studies of lead zirconate titanate Pb(ZrxTi1-x)O-3 (PZT), 0.10 less than or equal to x less than or equal to 0.80, and Nd-modified le ad titanate Pb1-3y/2NdyTiO3 (PNT), y = 0.02, 0.10, bulk ceramics were carri ed out at ambient temperatures between 4.2 and 297 K. Our measurements reve al splitting of the E + B-1 symmetry peak at low temperatures in both PZT a nd PNT samples. Splitting or a very asymmetrical line shape of the three ot her E(TO) peaks in the PZT and PNT samples was also found. These findings a re related to the precursor effects. We also discuss the phase stability of lead titanate based perovskites from the point of view of our experimental results and recent theoretical calculations. A simple model explaining the differences between the low-frequency Raman spectra of tetragonal and trig onal PZTs is outlined.