Competing Orders in PZN-xPT and PMN-xPT Relaxor Ferroelectrics

Neutron and x-ray scattering studies on relaxor ferroelectric systems Pb(Zn1/3Nb2/3)O-3 (PZN), Pb(Mg1/3Nb2/3)O-3 (PMN), and their solid Solutions with PbTiO3 (PT) have shown that inhomogeneities and disorder play important roles in the materials properties. Although a long-range polar order can be established at low temperature-sometimes with the help of an external electric field; short-range local structures called the polar nano-regions (PNR) still persist. Both the bulk structure and the PNR have been studied in details. The coexistence and competition of long- and short-range polar orders and how they affect the structural and dynamical properties of relaxor materials are discussed.