Competing orders in PZN-xPT and PMN-xPT relaxor ferroelectrics

摘要

Neutron and x-ray scattering studies on relaxor ferroelectric systems Pb(Zn_(1/3)Nb_(2/3))O_3 (PZN), Pb(Mg _(1/3)Nb_(2/3))O_3 (PMN), and their solid solutions with PbTiO_3 (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.