Evidence for oxygen vacancy inducing spontaneous normal-relaxor transition in complex perovskite ferroelectrics

The relaxor ferroelectrics-0.3Pb(Zn1/3Nb2/3)O-3-0.7(Pb,La)(Zr,Ti)O-3-have been produced by sintering in reductive nitrogen ambient and postannealing in oxygen ambient. The two kinds of specimens exhibited great differences in the conductivity as a function of temperature, which indicated a high concentration of oxygen vacancies in the as-sintered specimen. On the other hand, this specimen underwent an evident spontaneous normal-relaxation transition, whereas the as-annealed one did not. The corresponding reason has been analyzed on the basis of the facts, which provide some evidence that the interior stresses due to oxygen deficiency induce the spontaneous normal-relaxor transition in the specimen sintered in reductive ambient. (C) 2005 American Institute of Physics.