Chemical order influence on the phase transition in the relaxor Pb(Sc1/2Nb1/2)O3

The transitions from a relaxor state to a rhombohedral ferroelectric phase are studied in different Pb(Sc1/2Nb1/2)O-3 ceramics characterized by varied chemical ordering on the B site of the perovskite structure. The transition may arise at different temperatures, eventually in two stages in the same sample. The dielectric response reflects the density of polar domains and changes from relaxorlike (numerous polar nanodomains in the nearly fully ordered sample) to the relaxor-normal ferroelectric transition (in the disordered sample). The chemical order degree, as well as the spatial inhomogeneity of this order have to be taken into account to understand this behavior. (C) 2001 American Institute of Physics.