Phase diagram of the relaxor (1−x)Pb(Zn1/3Nb2/3)O3–xPbTiO3 investigated by dielectric and Raman spectroscopies

Lead zinc niobate–lead titanate[(1−x)Pb(Zn1/3Nb2/3)O3–xPbTiO3] (PZN–PT) crystals with x=4.5% and x=12% have been investigated using dielectric and Raman measurements over a range of temperatures. Above room temperature, dielectric measurements show that both compositions exhibit structural phase transitions according to the phase diagram proposed by Kuwata et al. [Ferroelectrics 387 (1981) 579]. Below room temperature, an anomaly at around 180 K for the x=12% sample is observed, suggesting another phase transition. Raman measurements are used to study all phase transitions.