SPONTANEOUS MICRO-MACRO FERROELECTRIC DOMAIN SWITCHING IN PBZRO3-DOPED PB(NI1/3NB2/3)O-3-PBTIO3 SYSTEM

The possibility of the existence of a spontaneous relaxer-normal ferroelectric transition was proposed and examined using 1-3 mol% PbZrO3-doped Pb(Ni1/3Nb2/3)O-3-PbTiO3 (PNN-PT) systems having tetragonal symmetry at room temperature. On cooling, the system with 60 mol% Pb(Ni1/3NTb2/3)O-3 underwent a spontaneous transition from a relaxer to a normal ferroelectric state. A microscopic examination demonstrated that the relaxer-normal ferroelectric transition corresponds to a micro-macro domain switching. Long-range ferroelectric domains below the transition temperature were characterized by twinlike 90 degrees macrodomains with tetragonal symmetry. The relaxer-normal transition was further correlated with the rhombohedral-tetragonal first-order phase transition.