Dynamics and Structure of PMN and PZN

Abstract

A review is given of recent neutron and x-ray scattering studies of the lead-oxide perovskite relaxor systems Pb(Zn1/3Nb2/3)O3-xPbTiO3 and Pb(Mg1/3Nb2/3)O3-xPbTiO3. X-ray measurements by Noheda et al. have established that these two systems exhibit nearly identical phase diagrams in which a rhombohedral-monoclinic-tetragonal structural sequence takes place with increasing PbTiO3 concentration. Recent high-energy x-ray and neutron measurements on single crystals of PZN and PMN-10PT, however, show that the rhombohedral distortions occur only in the outermost 20 - 40 microns, while the bulk of each crystal transforms into a new phase X, which has a nearly cubic unit cell. This situation is very similar to the structural behavior of pure PMN at Tc = 220 K. A simple model has been suggested that correlates phase X to the unique atomic displacements of the polar nanoregions, which are created at the Burns temperature.

conference proceeding for the NATO workshop on Disordered Ferroelectrics. To be published on Ferroelectrics

References in corpus (7)

• A tetragonal-to-monoclinic phase transition in a ferroelectric perovskite: the structure of PbZr(0.52)Ti(0.48)O3
• Monoclinic and triclinic phases in higher-order Devonshire theory
• Phase diagram of the relaxor ferroelectric (1-x)PbZn(1/3)Nb(2/3)O3-xPbTiO3
• Soft Mode Dynamics Above and Below the Burns Temperature in the Relaxor Pb(Mg_1/3Nb_2/3)O_3
• Universal Static and Dynamic Properties of the Structural Transition in Pb(Zn1/3Nb2/3)O3
• Ground State of Relaxor Ferroelectric $Pb(Z{n}_{1/3}N{b}_{2/3})O_3$
• Dynamical effects of the nanometer-sized polarized domains in Pb(Zn1/3Nb2/3)O3